Bump eslint-plugin-import from 2.29.1 to 2.31.0

Bumps [eslint-plugin-import](https://github.com/import-js/eslint-plugin-import) from 2.29.1 to 2.31.0.
- [Release notes](https://github.com/import-js/eslint-plugin-import/releases)
- [Changelog](https://github.com/import-js/eslint-plugin-import/blob/main/CHANGELOG.md)
- [Commits](https://github.com/import-js/eslint-plugin-import/compare/v2.29.1...v2.31.0)

---
updated-dependencies:
- dependency-name: eslint-plugin-import
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.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
+            - name: Install dependencies, run tests and build
-              run: npm install
+              run: npm run prepare:deploy
-
-            - name: Run Tests
-              run: npm run test:verbose
-
-            - name: Build the Project
-              run: npm run build:tsc
 
             - 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 +1,58 @@
+# 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
+
+- Add pre release building to release workflow on dev/* branches an version changes.
+
+
+### 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

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

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "ts-injex",
-  "version": "0.0.9",
+  "version": "0.1.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "ts-injex",
-      "version": "0.0.9",
+      "version": "0.1.0",
       "license": "MIT",
       "dependencies": {
         "eslint-plugin-prettier": "^5.2.1",
@@ -20,7 +20,7 @@
         "@typescript-eslint/parser": "^8.1.0",
         "axios": "^1.7.2",
         "eslint-plugin-deprecation": "^3.0.0",
-        "eslint-plugin-import": "^2.29.1",
+        "eslint-plugin-import": "^2.31.0",
         "eslint-plugin-jsdoc": "^50.2.2",
         "eslint-plugin-override": "https://github.com/PxaMMaxP/eslint-plugin-override",
         "istanbul-badges-readme": "^1.9.0",
@@ -1187,6 +1187,12 @@
         "url": "https://opencollective.com/unts"
       }
     },
+    "node_modules/@rtsao/scc": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/@rtsao/scc/-/scc-1.1.0.tgz",
+      "integrity": "sha512-zt6OdqaDoOnJ1ZYsCYGt9YmWzDXl4vQdKTyJev62gFhRGKdx7mcT54V9KIjg+d2wi9EXsPvAPKe7i7WjfVWB8g==",
+      "dev": true
+    },
     "node_modules/@shikijs/core": {
       "version": "1.13.0",
       "resolved": "https://registry.npmjs.org/@shikijs/core/-/core-1.13.0.tgz",
@@ -2995,9 +3001,9 @@
       }
     },
     "node_modules/eslint-module-utils": {
-      "version": "2.8.1",
+      "version": "2.12.0",
-      "resolved": "https://registry.npmjs.org/eslint-module-utils/-/eslint-module-utils-2.8.1.tgz",
+      "resolved": "https://registry.npmjs.org/eslint-module-utils/-/eslint-module-utils-2.12.0.tgz",
-      "integrity": "sha512-rXDXR3h7cs7dy9RNpUlQf80nX31XWJEyGq1tRMo+6GsO5VmTe4UTwtmonAD4ZkAsrfMVDA2wlGJ3790Ys+D49Q==",
+      "integrity": "sha512-wALZ0HFoytlyh/1+4wuZ9FJCD/leWHQzzrxJ8+rebyReSLk7LApMyd3WJaLVoN+D5+WIdJyDK1c6JnE65V4Zyg==",
       "dev": true,
       "dependencies": {
         "debug": "^3.2.7"
@@ -3157,34 +3163,36 @@
       }
     },
     "node_modules/eslint-plugin-import": {
-      "version": "2.29.1",
+      "version": "2.31.0",
-      "resolved": "https://registry.npmjs.org/eslint-plugin-import/-/eslint-plugin-import-2.29.1.tgz",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-import/-/eslint-plugin-import-2.31.0.tgz",
-      "integrity": "sha512-BbPC0cuExzhiMo4Ff1BTVwHpjjv28C5R+btTOGaCRC7UEz801up0JadwkeSk5Ued6TG34uaczuVuH6qyy5YUxw==",
+      "integrity": "sha512-ixmkI62Rbc2/w8Vfxyh1jQRTdRTF52VxwRVHl/ykPAmqG+Nb7/kNn+byLP0LxPgI7zWA16Jt82SybJInmMia3A==",
       "dev": true,
       "dependencies": {
-        "array-includes": "^3.1.7",
+        "@rtsao/scc": "^1.1.0",
-        "array.prototype.findlastindex": "^1.2.3",
+        "array-includes": "^3.1.8",
+        "array.prototype.findlastindex": "^1.2.5",
         "array.prototype.flat": "^1.3.2",
         "array.prototype.flatmap": "^1.3.2",
         "debug": "^3.2.7",
         "doctrine": "^2.1.0",
         "eslint-import-resolver-node": "^0.3.9",
-        "eslint-module-utils": "^2.8.0",
+        "eslint-module-utils": "^2.12.0",
-        "hasown": "^2.0.0",
+        "hasown": "^2.0.2",
-        "is-core-module": "^2.13.1",
+        "is-core-module": "^2.15.1",
         "is-glob": "^4.0.3",
         "minimatch": "^3.1.2",
-        "object.fromentries": "^2.0.7",
+        "object.fromentries": "^2.0.8",
-        "object.groupby": "^1.0.1",
+        "object.groupby": "^1.0.3",
-        "object.values": "^1.1.7",
+        "object.values": "^1.2.0",
         "semver": "^6.3.1",
+        "string.prototype.trimend": "^1.0.8",
         "tsconfig-paths": "^3.15.0"
       },
       "engines": {
         "node": ">=4"
       },
       "peerDependencies": {
-        "eslint": "^2 || ^3 || ^4 || ^5 || ^6 || ^7.2.0 || ^8"
+        "eslint": "^2 || ^3 || ^4 || ^5 || ^6 || ^7.2.0 || ^8 || ^9"
       }
     },
     "node_modules/eslint-plugin-import/node_modules/debug": {
@@ -4153,9 +4161,9 @@
       }
     },
     "node_modules/is-core-module": {
-      "version": "2.15.0",
+      "version": "2.15.1",
-      "resolved": "https://registry.npmjs.org/is-core-module/-/is-core-module-2.15.0.tgz",
+      "resolved": "https://registry.npmjs.org/is-core-module/-/is-core-module-2.15.1.tgz",
-      "integrity": "sha512-Dd+Lb2/zvk9SKy1TGCt1wFJFo/MWBPMX5x7KcvLajWTGuomczdQX61PvY5yK6SVACwpoexWo81IfFyoKY2QnTA==",
+      "integrity": "sha512-z0vtXSwucUJtANQWldhbtbt7BnL0vxiFjIdDLAatwhDYty2bad6s+rijD6Ri4YuYJubLzIJLUidCh09e1djEVQ==",
       "dev": true,
       "dependencies": {
         "hasown": "^2.0.2"

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ts-injex",
-  "version": "0.0.11",
+  "version": "0.1.0",
   "description": "Simple boilerplate code free dependency injection system for TypeScript.",
   "type": "module",
   "main": "./dist/index.js",
@@ -22,7 +22,8 @@
     "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",
@@ -39,7 +40,7 @@
     "@typescript-eslint/eslint-plugin": "^8.1.0",
     "@typescript-eslint/parser": "^8.1.0",
     "eslint-plugin-deprecation": "^3.0.0",
-    "eslint-plugin-import": "^2.29.1",
+    "eslint-plugin-import": "^2.31.0",
     "eslint-plugin-jsdoc": "^50.2.2",
     "eslint-plugin-override": "https://github.com/PxaMMaxP/eslint-plugin-override",
     "jest": "^29.7.0",

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.*'));
+        });
     });
 }
 

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

@@ -1,4 +1,3 @@
-import { Identifier } from 'src/types/Identifier';
 import type { Inject } from '../decorators/Inject';
 import type { Register } from '../decorators/Register';
 import type { RegisterInstance } from '../decorators/RegisterInstance';
@@ -8,6 +7,7 @@ import { ImplementsStatic } from '../helper/ImplementsStatic';
 import { DependencyResolutionError } from '../interfaces/Exceptions';
 import { IDependency } from '../interfaces/IDependency';
 import { ITSinjex, ITSinjex_ } from '../interfaces/ITSinjex';
+import { Identifier } from '../types/Identifier';
 
 /**
  * # TSinjex
@@ -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

@@ -1,5 +1,11 @@
-import { Identifier } from 'src/types/Identifier';
+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();
+         * Function to evaluate the dependency lazily
-        // Get the DI container instance
+         * to avoid circular dependencies, not found dependencies, etc.
-        const diContainer = TSinjex.getInstance();
+         * @returns The resolved dependency or undefined if the dependency is not found.
-
+         */
-        // Function to evaluate the dependency lazily
+        const resolve = (): T | undefined => {
-        // to avoid circular dependencies, not found dependencies, etc.
+            return TSinjex.getInstance().resolve<T>(identifier, necessary);
-        const evaluate = (): T | undefined => {
-            return diContainer.resolve<T>(identifier, necessary);
         };
 
-        // Define the property
         Object.defineProperty(target, propertyKey, {
             get() {
-                // If the property is not defined, evaluate the dependency
+                let instance: T | U | undefined;
-                if (!this.hasOwnProperty(privatePropertyKey)) {
-                    if (init) {
-                        try {
-                            this[privatePropertyKey] = init(evaluate() as T);
-                        } catch (error) {
-                            if (necessary) {
-                                throw error;
-                            }
-                        }
-                    } else {
-                        this[privatePropertyKey] = evaluate();
-                    }
-                }
 
-                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) {
+             * Make the property configurable to allow replacing it
-            //     this[privatePropertyKey] = value;
+             */
-            // },
+            configurable: true,
-            enumerable: true,
-            configurable: false,
         });
     };
 }
+
+/**
+ * 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

@@ -1,5 +1,5 @@
-import { Identifier } from 'src/types/Identifier';
 import { TSinjex } from '../classes/TSinjex';
+import { Identifier } from '../types/Identifier';
 
 /**
  * A decorator to register a class in the **TSinjex** DI (Dependency Injection) container.

src/decorators/RegisterInstance.ts

@@ -1,5 +1,5 @@
-import { Identifier } from 'src/types/Identifier';
 import { TSinjex } from '../classes/TSinjex';
+import { Identifier } from '../types/Identifier';
 import { InitDelegate } from '../types/InitDelegate';
 
 /**

src/functions/register.ts

@@ -1,5 +1,5 @@
-import { Identifier } from 'src/types/Identifier';
 import { TSinjex } from '../classes/TSinjex';
+import { Identifier } from '../types/Identifier';
 
 /**
  * Register a dependency.

src/functions/resolve.ts

@@ -1,6 +1,6 @@
-import { Identifier } from 'src/types/Identifier';
 import { TSinjex } from '../classes/TSinjex';
 import { DependencyResolutionError } from '../interfaces/Exceptions';
+import { Identifier } from '../types/Identifier';
 
 /**
  * Resolve a dependency.

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) {
+    constructor(identifier: Identifier) {
-        super(`Dependency ${identifier} could not be resolved.`);
+        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/interfaces/ITSinjex.ts

@@ -1,5 +1,5 @@
-import { Identifier } from 'src/types/Identifier';
 import { DependencyResolutionError } from './Exceptions';
+import { Identifier } from '../types/Identifier';
 
 /**
  * Static TSInjex Interface

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;