Feature/integrate register instance in register (#2)

* refactor: consolidate registration decorators

- Introduced `Register` decorator to handle class and instance registration in the DI container.
- Deprecated `RegisterInstance` in favor of `Register`, which now internally handles instance registration.
- Added support for marking dependencies as deprecated with a warning logged upon first resolution.
- Updated documentation with examples and notes on deprecation.

* tests: add mode parameter to RegisterInstanceDecorator

- Introduced a `mode` parameter to the `test_RegisterInstanceDecorator` function allowing 'instance' or 'standalone' modes.
- Updated test cases to utilize the new `mode` parameter when registering an instance.
- Disabled specific ESLint rule in `Decorators.test.ts` for deprecation warnings.
- Added an additional test call to `test_RegisterInstanceDecorator` with 'instance' mode.

* docs: Reflect changes to changelog

* refactor: add region tags for overloads in Register.ts

* docs: Reflect changes to changelog

* refactor: consolidate registration decorators

- Introduced `Register` decorator to handle class and instance registration in the DI container.
- Deprecated `RegisterInstance` in favor of `Register`, which now internally handles instance registration.
- Added support for marking dependencies as deprecated with a warning logged upon first resolution.
- Updated documentation with examples and notes on deprecation.

* tests: add mode parameter to RegisterInstanceDecorator

- Introduced a `mode` parameter to the `test_RegisterInstanceDecorator` function allowing 'instance' or 'standalone' modes.
- Updated test cases to utilize the new `mode` parameter when registering an instance.
- Disabled specific ESLint rule in `Decorators.test.ts` for deprecation warnings.
- Added an additional test call to `test_RegisterInstanceDecorator` with 'instance' mode.

* docs: Reflect changes to changelog

* refactor: add region tags for overloads in Register.ts

* docs: Reflect changes to changelog

* docs: Reflect changes to changelog und push version

.github/workflows/CreateRelease.yml

@@ -4,6 +4,7 @@ on:
     push:
         branches:
             - main
+            - 'dev/*'
         paths:
             - 'package.json'
     workflow_dispatch: # Allows manual execution of the workflow.
@@ -22,20 +23,14 @@ jobs:
               with:
                   node-version: '20.8.0'
 
-            - name: Install Dependencies
-              run: npm install
-
-            - name: Run Tests
-              run: npm run test:verbose
-
-            - name: Build the Project
-              run: npm run build:tsc
+            - name: Install dependencies, run tests and build
+              run: npm run prepare:deploy
 
             - name: Get the version
               id: get_version
               run: |
                   VERSION=$(npm run version:show | tail -n 1)
-                  echo "VERSION=$VERSION" >> $GITHUB_ENV
+                  echo "VERSION=v$VERSION" >> $GITHUB_ENV
               shell: bash
 
             - name: Get previous release tag
@@ -77,8 +72,9 @@ jobs:
                   echo "Generating release notes from ${{ env.PREVIOUS_TAG }} to HEAD..."
                   repo_url=$(git config --get remote.origin.url)
                   notes=$(git log ${{ env.PREVIOUS_TAG }}..HEAD --pretty=format:"- [\`%h\`]($repo_url/commit/%H): %s%n")
-                  echo "Release notes:"
+                  echo "See [CHANGELOG.md](./CHANGELOG.md) for more details."
                   echo "$notes"
+                  echo ""
                   echo "### Changes in this release" > release_notes.md
                   echo "$notes" >> release_notes.md
               shell: bash
@@ -90,17 +86,6 @@ jobs:
                   git config --local user.email "actions@github.com"
               shell: bash
 
-            # - name: Create temporary branch
-            #   id: create_temp_branch
-            #   if: steps.check_version.outputs.skip_release == 'false'
-            #   run: |
-            #       git checkout --orphan release/v${{ env.VERSION }}
-            #       git reset
-            #       rm -f .gitignore
-            #       git add README.md package.json LICENSE dist/ src/ tsconfig.json
-            #       git commit -m "Prepare files for release ${{ env.VERSION }}"
-            #   shell: bash
-
             - name: Create and push tag
               id: create_tag
               if: steps.check_version.outputs.skip_release == 'false'
@@ -111,6 +96,15 @@ jobs:
                   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
               shell: bash
 
+            - name: Set Release Prerelease Flag
+              id: set_prerelease_flag
+              run: |
+                  if [[ "${{ github.ref }}" == "refs/heads/main" ]]; then
+                    echo "PRE_RELEASE=false" >> $GITHUB_ENV
+                  elif [[ "${{ github.ref }}" == refs/heads/dev/* ]]; then
+                    echo "PRE_RELEASE=true" >> $GITHUB_ENV
+                  fi
+
             - name: Release
               if: steps.check_version.outputs.skip_release == 'false'
               uses: softprops/action-gh-release@v2
@@ -118,6 +112,6 @@ jobs:
                   tag_name: ${{ env.VERSION }}
                   name: Release ${{ env.VERSION }}
                   body_path: release_notes.md
-                  prerelease: true
+                  prerelease: ${{ env.PRE_RELEASE }}
               env:
                   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/ValidateBranchName.yml

@@ -3,7 +3,7 @@ name: Validate Branch Name on Pull Request
 on:
     pull_request:
         branches:
-            - main
+            - UNDEFINED
 
 jobs:
     validate-branch-name-on-pull-request:

CHANGELOG.md

@@ -0,0 +1,95 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+
+### Deprecated
+
+
+### Removed
+
+
+### Fixed
+
+
+### Security
+
+## [0.3.0]
+
+### Added
+
+- refactor: consolidate registration decorators
+  Introduced Register decorator to handle class and instance registration in the DI container.
+  Deprecated RegisterInstance in favor of Register, which now internally handles instance registration.
+  Added support for marking dependencies as deprecated with a warning logged upon first resolution.
+  Updated documentation with examples and notes on deprecation.
+- tests: add mode parameter to RegisterInstanceDecorator
+  Introduced a mode parameter to the test_RegisterInstanceDecorator function allowing 'instance' or 'standalone' modes.
+  Updated test cases to utilize the new mode parameter when registering an instance.
+  Disabled specific ESLint rule in Decorators.test.ts for deprecation warnings.
+  Added an additional test call to test_RegisterInstanceDecorator with 'instance' mode.
+- refactor: add region tags for overloads in Register.ts
+
+## [0.2.0]
+
+### Added
+
+- Add pre release building to release workflow on dev/* branches an version changes.
+- feat: Introduced a new CLI command `tsinjex-generate` to automate the generation of import statements for registered dependencies.  
+  The command scans `.ts` files for `@Register` and `@RegisterInstance` decorators and generates an `auto-imports.ts` file.  
+  This ensures that all registered dependencies are automatically included without requiring manual imports.  
+  The CLI can be executed via `npx tsinjex-generate` or added as a script in `package.json` for easier integration.
+
+
+### Deprecated
+
+
+### Removed
+
+
+### Fixed
+
+
+### Security
+
+## [0.0.14]
+
+### Added
+
+- Added **ChangeLog** file and format it according to [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
+- Added reference to **Semantic Versioning** in the changelog file. (History will be updated on time).
+- Version format is now `v0.0.0` instead of `0.0.0`. Changes to this are also reflected in the workflos.
+- Add `Identifiers` and `Jest` Sections to the `README.md` file.
+- feat: Add new Error `InitializationError` to reflect errors during initialization of a dependency.
+- feat: Add initialization error handling and refactor Inject.
+- feat: After injecting a dependency, the lazzy loading getter will be replaced with the dependency itself.
+- feat: remove the use of a private property to store the injected dependencies. Now the dependencies are stored in the property itself.
+- test: Add tests for the new features.
+
+
+### Deprecated
+
+- Deprecated the old version format `0.0.0`.
+
+### Removed
+
+
+### Fixed
+
+
+### Security
+
+
+---
+
+[unreleased]: https://github.com/PxaMMaxP/TSinjex/compare/0.0.14...HEAD
+[0.0.14]: https://github.com/PxaMMaxP/TSinjex/compare/0.0.13...v0.0.14
+[0.2.00]: https://github.com/PxaMMaxP/TSinjex/compare/0.0.14...v0.2.0
+[0.3.00]: https://github.com/PxaMMaxP/TSinjex/compare/0.2.0...v0.3.0

README.md

@@ -6,8 +6,14 @@
 
 ## Configuration
 
+### Identifiers
+
+Strings and symbols are possible for the **identifiers**.
+
 ### Jest
 
+For the use of TSinjex with Jest, the corresponding source files can be found under `./src` of the TSinjex node_module folder. To use these files, the `moduleNameMapper` must be configured in the Jest configuration file. The following example shows how to configure the Jest configuration file to use the source files of TSinjex.
+
 #### Example jest setup
 
 ```ts

bin/generate-imports.cjs

@@ -0,0 +1,111 @@
+#!/usr/bin/env node
+
+const fs = require('fs');
+const path = require('path');
+const yargs = require('yargs');
+
+// CLI argument parsing
+const argv = yargs
+  .option('src', {
+    alias: 's',
+    type: 'string',
+    description: 'Directory to search for files',
+    default: 'src',
+  })
+  .option('output', {
+    alias: 'o',
+    type: 'string',
+    description: 'Path to the output file',
+    default: 'src/auto-imports.ts',
+  })
+  .option('pattern', {
+    alias: 'p',
+    type: 'string',
+    description: 'File pattern to search for (e.g., .ts, .js)',
+    default: '.ts',
+  })
+  .help()
+  .argv;
+
+// Fixed RegEx patterns for decorator detection
+const SEARCH_PATTERNS = [
+  /^@Register(?:<(.+)?>)?\(\s*["']{1}(.+)?["']{1}\s*,?\s*(true|false)?\s*\)/m, // Matches @Register(...)
+  /^@RegisterInstance(?:<(.+)?>)?\(\s*["']{1}(.+)?["']{1}\s*,?\s*(.+)?\s*\)/m, // Matches @RegisterInstance(...)
+];
+
+const FILE_PATTERN = argv.pattern.startsWith('.') ? argv.pattern : `.${argv.pattern}`; // Ensure the pattern starts with a dot
+
+/**
+ * Recursively searches for all files in a directory matching the specified pattern.
+ * @param {string} dirPath - The directory to search.
+ * @returns {string[]} - List of matching files.
+ */
+function getAllFiles(dirPath) {
+  let files = fs.readdirSync(dirPath);
+  let arrayOfFiles = [];
+
+  files.forEach((file) => {
+    const fullPath = path.join(dirPath, file);
+    if (fs.statSync(fullPath).isDirectory()) {
+      arrayOfFiles = arrayOfFiles.concat(getAllFiles(fullPath));
+    } else if (file.endsWith(FILE_PATTERN)) {
+      arrayOfFiles.push(fullPath);
+    }
+  });
+
+  return arrayOfFiles;
+}
+
+/**
+ * Filters files that contain at least one of the specified regex patterns.
+ * @param {string[]} files - List of files to check.
+ * @returns {string[]} - Files that contain at least one of the specified patterns.
+ */
+function findFilesWithPattern(files) {
+  return files.filter((file) => {
+    const content = fs.readFileSync(file, 'utf8');
+    return SEARCH_PATTERNS.some((pattern) => pattern.test(content));
+  });
+}
+
+/**
+ * Generates an import file containing imports for all found files.
+ * @param {string[]} files - List of relevant files.
+ * @returns {string} - Generated import code.
+ */
+function generateImports(files) {
+  return files.map((file) => `import '${file.replace(/\\/g, '/')}';`).join('\n') + '\n';
+}
+
+/**
+ * Main function that executes the script.
+ */
+function main() {
+  try {
+    const srcDir = path.resolve(process.cwd(), argv.src);
+    const outputFile = path.resolve(process.cwd(), argv.output);
+
+    if (!fs.existsSync(srcDir)) {
+      console.error(`❌ Error: The directory '${srcDir}' does not exist.`);
+      process.exit(1);
+    }
+
+    const allFiles = getAllFiles(srcDir);
+    const filesWithPattern = findFilesWithPattern(allFiles);
+
+    if (filesWithPattern.length === 0) {
+      console.log(`ℹ️ No ${FILE_PATTERN} files found matching the specified decorator patterns.`);
+      return;
+    }
+
+    const importContent = generateImports(filesWithPattern);
+    fs.writeFileSync(outputFile, importContent);
+
+    console.log(`✅ Imports successfully generated: ${outputFile}`);
+  } catch (error) {
+    console.error('❌ An error occurred:', error.message);
+    process.exit(1);
+  }
+}
+
+main();

package.json

@@ -1,10 +1,13 @@
 {
   "name": "ts-injex",
-  "version": "0.0.13",
+  "version": "0.3.0",
   "description": "Simple boilerplate code free dependency injection system for TypeScript.",
   "type": "module",
   "main": "./dist/index.js",
   "types": "./dist/index.d.ts",
+  "bin": {
+    "tsinjex-generate": "./bin/generate-imports.cjs"
+  },
   "scripts": {
     "prepare": "npm run build",
     "build": "npm run build:tsc",
@@ -22,7 +25,8 @@
     "docs:fix:coverage": "node scripts/fix-coverage-paths.cjs",
     "docs:generate:badge": "node scripts/generate-badge.cjs",
     "docs:fix:escape": "node scripts/replace-doc-escaping.cjs",
-    "version:show": "node -e \"console.log(require('./package.json').version)\""
+    "version:show": "node -e \"console.log(require('./package.json').version)\"",
+    "prepare:deploy": "npm install && npm run test:verbose && npm run build:tsc"
   },
   "repository": {
     "type": "git",
@@ -59,4 +63,4 @@
     "LICENSE",
     "package.json"
   ]
-}
+}

src/__tests__/Decorators.spec.ts

@@ -1,3 +1,4 @@
+/* istanbul ignore file */
 /* eslint-disable @typescript-eslint/no-explicit-any */
 import { Inject } from 'src/decorators/Inject';
 import { DependencyResolutionError } from 'src/interfaces/Exceptions';
@@ -117,6 +118,130 @@ export function test_InjectDecorator(
             }
             expect(_error).toBeInstanceOf(DependencyResolutionError);
         });
+
+        it('should replace the property with the resolved dependency', () => {
+            container.register('MockDependencyIdentifier', {
+                value: 'test-value',
+            });
+
+            class TestClass {
+                @Inject('MockDependencyIdentifier')
+                private readonly _dependency!: any;
+
+                public getDependency() {
+                    return this._dependency;
+                }
+
+                public isDependencyTypeofFunction() {
+                    return typeof this._dependency === 'function';
+                }
+            }
+
+            const instance = new TestClass();
+
+            expect(instance.getDependency().value).toBe('test-value');
+
+            expect(instance.isDependencyTypeofFunction()).toBe(false);
+            expect(instance.getDependency().value).toBe('test-value');
+        });
+
+        it('should use a empty initializer when none is provided but true', () => {
+            container.register(
+                'MockDependencyIdentifier',
+                class X {
+                    public value: string = 'test-value';
+                    constructor() {}
+                },
+            );
+
+            class TestClass {
+                @Inject('MockDependencyIdentifier', true)
+                private readonly _dependency!: any;
+
+                public getDependency() {
+                    return this._dependency;
+                }
+            }
+
+            const instance = new TestClass();
+            expect(instance.getDependency().value).toBe('test-value');
+        });
+
+        it('should throw an error when the dependency has no instantiation method', () => {
+            container.register('MockDependencyIdentifier', {
+                value: 'test-value',
+            });
+
+            class TestClass {
+                @Inject('MockDependencyIdentifier', true)
+                private readonly _dependency!: any;
+
+                public getDependency() {
+                    return this._dependency;
+                }
+            }
+
+            expect(() => {
+                const instance = new TestClass();
+                instance.getDependency();
+            }).toThrow(new RegExp('No instantiation method found for.*'));
+        });
+
+        it('should not throw an error when the dependency has no instantiation method if not necessary', () => {
+            container.register('MockDependencyIdentifier', {
+                value: 'test-value',
+            });
+
+            class TestClass {
+                @Inject('MockDependencyIdentifier', true, false)
+                private readonly _dependency!: any;
+
+                public getDependency() {
+                    return this._dependency;
+                }
+            }
+
+            expect(() => {
+                const instance = new TestClass();
+                instance.getDependency();
+            }).not.toThrow(new RegExp('No instantiation method found for.*'));
+        });
+
+        it('should throw an error when the dependency cannot be resolved', () => {
+            container.register('MockDependencyIdentifier', null);
+
+            class TestClass {
+                @Inject('MockDependencyIdentifier', true)
+                private readonly _dependency!: any;
+
+                public getDependency() {
+                    return this._dependency;
+                }
+            }
+
+            expect(() => {
+                const instance = new TestClass();
+                instance.getDependency();
+            }).toThrow(new RegExp('.*could not be resolved.*'));
+        });
+
+        it('should not throw an error when the dependency cannot be resolved if not necessary', () => {
+            container.register('MockDependencyIdentifier', null);
+
+            class TestClass {
+                @Inject('MockDependencyIdentifier', true, false)
+                private readonly _dependency!: any;
+
+                public getDependency() {
+                    return this._dependency;
+                }
+            }
+
+            expect(() => {
+                const instance = new TestClass();
+                instance.getDependency();
+            }).not.toThrow(new RegExp('.*could not be resolved.*'));
+        });
     });
 }
 
@@ -157,6 +282,7 @@ export function test_RegisterInstanceDecorator(
     Container: ITSinjex_,
     // eslint-disable-next-line @typescript-eslint/no-unsafe-function-type
     registerInstance: Function,
+    mode: 'instance' | 'standalone' = 'standalone',
 ): void {
     describe('RegisterInstance Decorator Tests', () => {
         let container: ITSinjex;
@@ -170,7 +296,10 @@ export function test_RegisterInstanceDecorator(
         });
 
         it('should register an instance of a dependency', () => {
-            @registerInstance('InstanceIdentifier')
+            @registerInstance(
+                'InstanceIdentifier',
+                mode === 'instance' ? 'instance' : undefined,
+            )
             class TestClass {
                 private readonly _dependency!: any;
 
@@ -212,7 +341,10 @@ export function test_RegisterInstanceDecorator(
         });
 
         it('should register an instance of a dependency and get it on set', () => {
-            @registerInstance('InstanceIdentifier')
+            @registerInstance(
+                'InstanceIdentifier',
+                mode === 'instance' ? 'instance' : undefined,
+            )
             class TestClass {
                 private readonly _dependency!: any;
 

src/__tests__/Decorators.test.ts

@@ -1,3 +1,4 @@
+/* eslint-disable deprecation/deprecation */
 import { TSinjex } from 'src/classes/TSinjex';
 import { Inject } from 'src/decorators/Inject';
 import { Register } from 'src/decorators/Register';
@@ -13,3 +14,5 @@ test_InjectDecorator(TSinjex, Inject);
 test_RegisterDecorator(TSinjex, Register);
 
 test_RegisterInstanceDecorator(TSinjex, RegisterInstance);
+
+test_RegisterInstanceDecorator(TSinjex, Register, 'instance');

src/__tests__/Functions.spec.ts

@@ -1,3 +1,4 @@
+/* istanbul ignore file */
 /* eslint-disable @typescript-eslint/no-explicit-any */
 import { ITSinjex, ITSinjex_ } from 'src/interfaces/ITSinjex';
 

src/__tests__/ITSinjex.spec.ts

@@ -1,3 +1,4 @@
+/* istanbul ignore file */
 import { ITSinjex_, ITSinjex } from '../interfaces/ITSinjex';
 
 /**

src/classes/TSinjex.ts

@@ -114,7 +114,7 @@ export class TSinjex implements ITSinjex {
         }
 
         if (dependency.deprecated) {
-            console.warn(`Dependency ${identifier} is deprecated`);
+            console.warn(`Dependency ${identifier.toString()} is deprecated`);
 
             // Remove the deprecation warning; it should only be logged once.
             dependency.deprecated = false;

src/decorators/Inject.ts

@@ -1,3 +1,9 @@
+import {
+    DependencyResolutionError,
+    InitializationError,
+    InjectorError,
+    NoInstantiationMethodError,
+} from 'src/interfaces/Exceptions';
 import { TSinjex } from '../classes/TSinjex';
 import { Identifier } from '../types/Identifier';
 import { InitDelegate } from '../types/InitDelegate';
@@ -8,12 +14,17 @@ import { InitDelegate } from '../types/InitDelegate';
  * @template U The type of the property to be injected.
  * @param identifier The identifier used to resolve the class in the DI container.
  * @see {@link Identifier} for more information on identifiers.
- * @param init An optional initializer function to transform the dependency before injection.
+ * @param init Optional an initializer function to transform the dependency before injection
+ * or true to instantiate the dependency if it has a constructor.
  * @see {@link InitDelegate} for more information on initializer functions.
  * @param necessary If true, throws an error if the dependency is not found.
  * @returns The resolved dependency or undefined if the dependency is not necessary
  * and not found, or throws an error if the dependency is necessary and not found.
- * @throws A {@link DependencyResolutionError} if the dependency is not found and necessary.
+ * @throws **Only throws errors if the dependency is necessary.**
+ * @throws A {@link DependencyResolutionError} if the dependency is not found.
+ * @throws A {@link InjectorError} if an error occurs during the injection process.
+ * @throws A {@link NoInstantiationMethodError} if the dependency does not have a constructor.
+ * @throws An {@link InitializationError} if an error occurs during the initialization process.
  * @example
  * ```ts
  * class MyClass {
@@ -31,47 +42,110 @@ import { InitDelegate } from '../types/InitDelegate';
  */
 export function Inject<T, U>(
     identifier: Identifier,
-    init?: InitDelegate<T, U>,
+    init?: InitDelegate<T, U> | true,
     necessary = true,
 ) {
     return function (target: unknown, propertyKey: string | symbol): void {
-        // Unique symbol to store the private property
-        const privatePropertyKey: unique symbol = Symbol();
-        // Get the DI container instance
-        const diContainer = TSinjex.getInstance();
-
-        // Function to evaluate the dependency lazily
-        // to avoid circular dependencies, not found dependencies, etc.
-        const evaluate = (): T | undefined => {
-            return diContainer.resolve<T>(identifier, necessary);
+        /**
+         * Function to evaluate the dependency lazily
+         * to avoid circular dependencies, not found dependencies, etc.
+         * @returns The resolved dependency or undefined if the dependency is not found.
+         */
+        const resolve = (): T | undefined => {
+            return TSinjex.getInstance().resolve<T>(identifier, necessary);
         };
 
-        // Define the property
         Object.defineProperty(target, propertyKey, {
             get() {
-                // If the property is not defined, evaluate the dependency
-                if (!this.hasOwnProperty(privatePropertyKey)) {
-                    if (init) {
-                        try {
-                            this[privatePropertyKey] = init(evaluate() as T);
-                        } catch (error) {
-                            if (necessary) {
-                                throw error;
-                            }
-                        }
-                    } else {
-                        this[privatePropertyKey] = evaluate();
-                    }
-                }
+                let instance: T | U | undefined;
 
-                return this[privatePropertyKey];
+                const dependency: T | undefined = tryAndCatch(
+                    () => resolve(),
+                    necessary,
+                    identifier,
+                    DependencyResolutionError,
+                );
+
+                if (dependency != null) {
+                    const initFunction: (() => U) | undefined =
+                        typeof init === 'function' && dependency != null
+                            ? (): U => init(dependency)
+                            : init === true && hasConstructor(dependency)
+                              ? (): U => new dependency() as U
+                              : undefined;
+
+                    if (init == null) instance = dependency;
+                    else if (initFunction != null)
+                        instance = tryAndCatch(
+                            initFunction,
+                            necessary,
+                            identifier,
+                            InitializationError,
+                        );
+                    else if (necessary)
+                        throw new NoInstantiationMethodError(identifier);
+                } else if (necessary)
+                    throw new DependencyResolutionError(identifier);
+
+                /**
+                 * Replace itself with the resolved dependency
+                 * for performance reasons.
+                 */
+                Object.defineProperty(this, propertyKey, {
+                    value: instance,
+                    writable: false,
+                    enumerable: false,
+                    configurable: false,
+                });
+
+                return instance;
             },
-            // Not necessary to set the property
-            // set(value: PropertieType) {
-            //     this[privatePropertyKey] = value;
-            // },
-            enumerable: true,
-            configurable: false,
+            /**
+             * Make the property configurable to allow replacing it
+             */
+            configurable: true,
         });
     };
 }
+
+/**
+ * Tries to execute a function and catches any errors that occur.
+ * If the function is necessary and an error occurs, it throws the error
+ * with the specified error class and identifier.
+ * @param fn The function to execute.
+ * @param necessary If true, throws an error if an error occurs.
+ * @param identifier The identifier of the dependency.
+ * @param errorClass The error class to throw if an error occurs.
+ * @returns The result of the function or undefined if an error occurs and the function is not necessary.
+ */
+function tryAndCatch<ReturnType, ErrorType>(
+    fn: () => ReturnType,
+    necessary: boolean,
+    identifier?: Identifier,
+    errorClass?: ErrorType,
+): ReturnType | undefined {
+    try {
+        return fn();
+    } catch (error) {
+        if (necessary)
+            throw new (errorClass != null ? errorClass : error)(
+                identifier ?? 'not specified',
+                error,
+            );
+        else return undefined;
+    }
+}
+
+/**
+ * Checks if an object has a constructor.
+ * @param obj The object to check.
+ * @returns True if the object has a constructor, false otherwise.
+ */
+function hasConstructor<T>(obj: T): obj is T & { new (): unknown } {
+    const _obj = obj as unknown as { prototype?: { constructor?: unknown } };
+
+    return (
+        _obj?.prototype != null &&
+        typeof _obj.prototype.constructor === 'function'
+    );
+}

src/decorators/Register.ts

@@ -1,6 +1,134 @@
+import { InitDelegate } from 'src/types/InitDelegate';
 import { TSinjex } from '../classes/TSinjex';
 import { Identifier } from '../types/Identifier';
 
+//#region Overloads
+
+/**
+ * A decorator to register a class in the **TSinjex** DI (Dependency Injection) container.
+ * @template TargetType The type of the class to be registered.
+ * @param identifier The identifier used to register the class in the DI container.
+ * @see {@link Identifier} for more information on identifiers.
+ * @param deprecated If true, the dependency is deprecated and a warning
+ * is logged only once upon the first resolution of the dependency.
+ * @returns The decorator function to be applied on the class.
+ * @example
+ * ```ts
+ * \@Register('MyClassIdentifier')
+ * class MyClass {
+ *   // ...
+ * }
+ * ```
+ * @example
+ * ```ts
+ * \@Register('MyClassIdentifier', true)
+ * class MyClass {
+ *   // ...
+ * }
+ * ```
+ */
+export function Register<
+    TargetType extends new (...args: unknown[]) => InstanceType<TargetType>,
+>(
+    identifier: Identifier,
+    deprecated?: boolean,
+): (constructor: TargetType, ...args: unknown[]) => void;
+
+/**
+ * A decorator to register an instance of a class in the DI (Dependency Injection) container.
+ * @template TargetType The type of the class whose instance is to be registered.
+ * @param identifier The identifier used to register the instance in the DI container.
+ * @see {@link Identifier} for more information on identifiers.
+ * @param shouldRegister Set to 'instance' to register the instance in the DI container
+ * with an empty constructor.
+ * @param deprecated If true, the dependency is deprecated and a warning
+ * is logged only once upon the first resolution of the dependency.
+ * @returns The decorator function to be applied on the class.
+ * @example
+ * ```ts
+ * \@RegisterInstance('MyClassInstanceIdentifier', 'instance')
+ * class MyClass {
+ *   // ...
+ * }
+ * ```
+ * @example
+ * ```ts
+ * \@RegisterInstance('MyClassInstanceIdentifier', 'instance', true)
+ * class MyClass {
+ *   // ...
+ * }
+ * ```
+ */
+export function Register<
+    TargetType extends new (..._args: unknown[]) => InstanceType<TargetType>,
+>(
+    identifier: Identifier,
+    shouldRegister: 'instance',
+    deprecated?: boolean,
+): (constructor: TargetType, ...args: unknown[]) => void;
+
+/**
+ * A decorator to register an instance of a class in the DI (Dependency Injection) container.
+ * @template TargetType The type of the class whose instance is to be registered.
+ * @param identifier The identifier used to register the instance in the DI container.
+ * @see {@link Identifier} for more information on identifiers.
+ * @param init An optional initializer function which get the constructor of the class
+ * as input and returns an instance of the class.
+ * @param deprecated If true, the dependency is deprecated and a warning
+ * is logged only once upon the first resolution of the dependency.
+ * @see {@link InitDelegate} for more information on initializer functions.
+ * @returns The decorator function to be applied on the class.
+ * @example
+ * ```ts
+ * \@RegisterInstance('MyClassInstanceIdentifier', (constructor) => new constructor())
+ * class MyClass {
+ *   // ...
+ * }
+ * ```
+ * @example
+ * ```ts
+ * \@RegisterInstance('MyClassInstanceIdentifier', (constructor) => new constructor(), true)
+ * class MyClass {
+ *   // ...
+ * }
+ * ```
+ */
+export function Register<
+    TargetType extends new (..._args: unknown[]) => InstanceType<TargetType>,
+>(
+    identifier: Identifier,
+    init?: InitDelegate<
+        TargetType & { new (..._args: unknown[]): InstanceType<TargetType> },
+        InstanceType<TargetType>
+    >,
+    deprecated?: boolean,
+): (constructor: TargetType, ...args: unknown[]) => void;
+
+//#endregion Overloads
+
+// eslint-disable-next-line jsdoc/require-jsdoc
+export function Register<
+    TargetType extends new (...args: unknown[]) => InstanceType<TargetType>,
+>(
+    identifier: Identifier,
+    arg1?:
+        | undefined
+        | boolean
+        | InitDelegate<TargetType, InstanceType<TargetType>>
+        | 'instance',
+    arg2?: boolean,
+): (constructor: TargetType, ...args: unknown[]) => void {
+    const deprecated = typeof arg1 === 'boolean' ? arg1 : arg2;
+    const init = typeof arg1 === 'function' ? arg1 : undefined;
+    const shouldRegisterInstance = arg1 === 'instance';
+
+    if (init == undefined && shouldRegisterInstance !== true) {
+        return _register(identifier, deprecated);
+    } else {
+        return _registerInstance(identifier, init, deprecated);
+    }
+}
+
 /**
  * A decorator to register a class in the **TSinjex** DI (Dependency Injection) container.
  * @template TargetType The type of the class to be registered.
@@ -17,7 +145,7 @@ import { Identifier } from '../types/Identifier';
  * }
  * ```
  */
-export function Register<
+function _register<
     TargetType extends new (...args: unknown[]) => InstanceType<TargetType>,
 >(identifier: Identifier, deprecated?: boolean) {
     return function (constructor: TargetType, ...args: unknown[]): void {
@@ -28,3 +156,111 @@ export function Register<
         diContainer.register(identifier, constructor, deprecated);
     };
 }
+
+/**
+ * A decorator to register an instance of a class in the DI (Dependency Injection) container.
+ * @template TargetType The type of the class whose instance is to be registered.
+ * @param identifier The identifier used to register the instance in the DI container.
+ * @see {@link Identifier} for more information on identifiers.
+ * @param init An optional initializer function which get the constructor of the class
+ * as input and returns an instance of the class.
+ * @param deprecated If true, the dependency is deprecated and a warning
+ * is logged only once upon the first resolution of the dependency.
+ * @see {@link InitDelegate} for more information on initializer functions.
+ * @returns The decorator function to be applied on the class.
+ * @example
+ * ```ts
+ * \@RegisterInstance('MyClassInstanceIdentifier', (constructor) => new constructor())
+ * class MyClass {
+ *   // ...
+ * }
+ * ```
+ */
+function _registerInstance<
+    TargetType extends new (..._args: unknown[]) => InstanceType<TargetType>,
+>(
+    identifier: Identifier,
+    init?: InitDelegate<
+        TargetType & { new (..._args: unknown[]): InstanceType<TargetType> },
+        InstanceType<TargetType>
+    >,
+    deprecated?: boolean,
+) {
+    return function (constructor: TargetType, ...args: unknown[]): void {
+        // Get the instance of the DI container
+        const diContainer = TSinjex.getInstance();
+        let instance: InstanceType<TargetType>;
+
+        // Create a proxy to instantiate the class when needed (Lazy Initialization)
+        let lazyProxy: unknown = new Proxy(
+            {},
+            {
+                get(target, prop, receiver) {
+                    ({ instance, lazyProxy } = initializeInstance<TargetType>(
+                        instance,
+                        init,
+                        constructor,
+                        args,
+                        lazyProxy,
+                    ));
+
+                    // Return the requested property of the instance
+                    return instance[prop as keyof InstanceType<TargetType>];
+                },
+                set(target, prop, value, receiver) {
+                    ({ instance, lazyProxy } = initializeInstance<TargetType>(
+                        instance,
+                        init,
+                        constructor,
+                        args,
+                        lazyProxy,
+                    ));
+
+                    // Set the requested property of the instance
+                    return (instance[prop as keyof InstanceType<TargetType>] =
+                        value);
+                },
+            },
+        );
+
+        // Register the lazy proxy in the DI container
+        diContainer.register(identifier, lazyProxy, deprecated);
+    };
+}
+
+/**
+ * Initializes the instance of the class.
+ * @template TargetType The type of the class whose instance is to be initialized.
+ * @param instance The instance of the class to be initialized.
+ * @param init The optional initializer function to initialize the instance.
+ * @param constructor The constructor of the class.
+ * @param args The arguments to be passed to the constructor of the class.
+ * @param lazyProxy The lazy proxy to instantiate the class when needed.
+ * @returns The initialized instance and the lazy proxy.
+ */
+function initializeInstance<
+    TargetType extends new (..._args: unknown[]) => InstanceType<TargetType>,
+>(
+    instance: InstanceType<TargetType>,
+    init:
+        | InitDelegate<
+              TargetType &
+                  (new (..._args: unknown[]) => InstanceType<TargetType>),
+              InstanceType<TargetType>
+          >
+        | undefined,
+    constructor: TargetType,
+    args: unknown[],
+    lazyProxy: unknown,
+): { instance: InstanceType<TargetType>; lazyProxy: unknown } {
+    if (instance == null) {
+        if (init) {
+            instance = init(constructor);
+        } else {
+            instance = new constructor(...args);
+        }
+    }
+    lazyProxy = instance;
+
+    return { instance, lazyProxy };
+}

src/decorators/RegisterInstance.ts

@@ -1,4 +1,4 @@
-import { TSinjex } from '../classes/TSinjex';
+import { Register } from './Register';
 import { Identifier } from '../types/Identifier';
 import { InitDelegate } from '../types/InitDelegate';
 
@@ -9,6 +9,8 @@ import { InitDelegate } from '../types/InitDelegate';
  * @see {@link Identifier} for more information on identifiers.
  * @param init An optional initializer function which get the constructor of the class
  * as input and returns an instance of the class.
+ * @param deprecated If true, the dependency is deprecated and a warning
+ * is logged only once upon the first resolution of the dependency.
  * @see {@link InitDelegate} for more information on initializer functions.
  * @returns The decorator function to be applied on the class.
  * @example
@@ -18,6 +20,7 @@ import { InitDelegate } from '../types/InitDelegate';
  *   // ...
  * }
  * ```
+ * @deprecated Use {@link Register} instead. This decorator already uses the {@link Register} decorator internally.
  */
 export function RegisterInstance<
     TargetType extends new (..._args: unknown[]) => InstanceType<TargetType>,
@@ -27,47 +30,10 @@ export function RegisterInstance<
         TargetType & { new (..._args: unknown[]): InstanceType<TargetType> },
         InstanceType<TargetType>
     >,
-) {
-    return function (constructor: TargetType, ...args: unknown[]): void {
-        // Get the instance of the DI container
-        const diContainer = TSinjex.getInstance();
-        let instance: InstanceType<TargetType>;
+    deprecated?: boolean,
+): (constructor: TargetType, ...args: unknown[]) => void {
+    const initDelegate = typeof init === 'function' ? init : undefined;
 
-        // Create a proxy to instantiate the class when needed (Lazy Initialization)
-        let lazyProxy: unknown = new Proxy(
-            {},
-            {
-                get(target, prop, receiver) {
-                    if (instance == null) {
-                        if (init) {
-                            instance = init(constructor);
-                        } else {
-                            instance = new constructor(...args);
-                        }
-                    }
-                    lazyProxy = instance;
-
-                    // Return the requested property of the instance
-                    return instance[prop as keyof InstanceType<TargetType>];
-                },
-                set(target, prop, value, receiver) {
-                    if (instance == null) {
-                        if (init) {
-                            instance = init(constructor);
-                        } else {
-                            instance = new constructor(...args);
-                        }
-                    }
-                    lazyProxy = instance;
-
-                    // Set the requested property of the instance
-                    return (instance[prop as keyof InstanceType<TargetType>] =
-                        value);
-                },
-            },
-        );
-
-        // Register the lazy proxy in the DI container
-        diContainer.register(identifier, lazyProxy);
-    };
+    if (initDelegate) return Register(identifier, initDelegate, deprecated);
+    else return Register(identifier, 'instance', deprecated);
 }

src/interfaces/Exceptions.ts

@@ -1,3 +1,4 @@
+import { Identifier } from 'src/types/Identifier';
 import { ITSinjex } from './ITSinjex';
 
 /**
@@ -23,8 +24,61 @@ export class DependencyResolutionError extends TSinjexError {
      * Creates a new instance of {@link DependencyResolutionError}
      * @param identifier **The identifier of the dependency**
      */
-    constructor(identifier: string) {
-        super(`Dependency ${identifier} could not be resolved.`);
+    constructor(identifier: Identifier) {
+        super(`Dependency ${identifier.toString()} could not be resolved.`);
         this.name = 'TSinjexResolutionError';
     }
 }
+
+/**
+ * Error class for Injector errors in {@link ITSinjex}.
+ * @see {@link ITSinjex.inject}
+ */
+export class InjectorError extends TSinjexError {
+    /**
+     * Creates a new instance of {@link InjectorError}
+     * @param identifier **The identifier of the dependency**
+     * @param originalError **The original error that caused the injection error**
+     */
+    constructor(identifier: Identifier, originalError?: Error) {
+        super(
+            `Error injecting dependency ${identifier.toString()} with error: "${originalError}"`,
+        );
+        this.name = 'TSinjexInjectorError';
+    }
+}
+
+/**
+ * Error class for missing instantiation methods in {@link ITSinjex}.
+ * @see {@link ITSinjex.inject}
+ */
+export class NoInstantiationMethodError extends TSinjexError {
+    /**
+     * Creates a new instance of {@link NoInstantiationMethodError}
+     * @param identifier **The identifier of the dependency**
+     */
+    constructor(identifier: Identifier) {
+        super(
+            `No instantiation method found for dependency ${identifier.toString()}.`,
+        );
+        this.name = 'TSinjexNoInstantiationMethodError';
+    }
+}
+
+/**
+ * Error class for errors during the initialization of a dependency in {@link ITSinjex}.
+ * @see {@link ITSinjex.inject}
+ */
+export class InitializationError extends TSinjexError {
+    /**
+     * Creates a new instance of {@link InitializationError}
+     * @param identifier **The identifier of the dependency**
+     * @param originalError **The original error that caused the initialization error**
+     */
+    constructor(identifier: Identifier, originalError?: Error) {
+        super(
+            `Error initializing dependency ${identifier.toString()} with error: "${originalError}"`,
+        );
+        this.name = 'TSinjexInitializationError';
+    }
+}

src/types/Identifier.ts

@@ -8,4 +8,4 @@
  * I.e. a class `ClassA` that implements the interface `IClassA` and is
  * registered as a dependent class is registered under the interface name `IClassA`.
  */
-export type Identifier = string;
+export type Identifier = string | symbol;