first

.eslintrc.js

+module.exports = {
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    project: 'tsconfig.json',
+    sourceType: 'module',
+  },
+  plugins: ['@typescript-eslint/eslint-plugin'],
+  extends: [
+    'plugin:@typescript-eslint/recommended',
+    'plugin:prettier/recommended',
+  ],
+  root: true,
+  env: {
+    node: true,
+    jest: true,
+  },
+  ignorePatterns: ['.eslintrc.js'],
+  rules: {
+    '@typescript-eslint/interface-name-prefix': 'off',
+    '@typescript-eslint/explicit-function-return-type': 'off',
+    '@typescript-eslint/explicit-module-boundary-types': 'off',
+    '@typescript-eslint/no-explicit-any': 'off',
+  },
+};

.gitignore

+# compiled output
+/dist
+/node_modules
+
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+
+# OS
+.DS_Store
+
+# Tests
+/coverage
+/.nyc_output
+
+# IDEs and editors
+/.idea
+.project
+.classpath
+.c9/
+*.launch
+.settings/
+*.sublime-workspace
+
+# IDE - VSCode
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+
+/data
+/output
+/config.yaml
\ No newline at end of file

.gitlab-ci.yml

+stages:
+  - build
+  - combine
+  - deploy
+variables:
+  GIT_DEPTH: "1"
+  CONTAINER_TEST_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
+  CONTAINER_TEST_ARM_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG-arm
+  CONTAINER_TEST_X86_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG-x86
+  CONTAINER_RELEASE_IMAGE: $CI_REGISTRY_IMAGE:latest
+before_script:
+  - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+build-x86:
+  stage: build
+  tags:
+    - docker
+  script:
+    - TARGET_IMAGE=$CONTAINER_TEST_X86_IMAGE
+    - docker build --pull -t $TARGET_IMAGE .
+    - docker push $TARGET_IMAGE
+build-arm:
+  stage: build
+  tags:
+    - docker-arm
+  script:
+    - TARGET_IMAGE=$CONTAINER_TEST_ARM_IMAGE
+    - docker build --pull -t $TARGET_IMAGE .
+    - docker push $TARGET_IMAGE
+combine:
+  stage: combine
+  tags:
+    - docker
+  script:
+    - TARGET_IMAGE=$CONTAINER_TEST_IMAGE
+    - SOURCE_IMAGE_2=$CONTAINER_TEST_ARM_IMAGE
+    - SOURCE_IMAGE_1=$CONTAINER_TEST_X86_IMAGE
+    - docker pull $SOURCE_IMAGE_1
+    - docker pull $SOURCE_IMAGE_2
+    - docker manifest create $TARGET_IMAGE --amend $SOURCE_IMAGE_1 --amend
+      $SOURCE_IMAGE_2
+    - docker manifest push $TARGET_IMAGE
+deploy_latest:
+  stage: deploy
+  tags:
+    - docker
+  script:
+    - TARGET_IMAGE=$CONTAINER_RELEASE_IMAGE
+    - SOURCE_IMAGE=$CONTAINER_TEST_IMAGE
+    - docker pull $SOURCE_IMAGE
+    - docker tag $SOURCE_IMAGE $TARGET_IMAGE
+    - docker push $TARGET_IMAGE
+  only:
+    - master
+deploy_tag:
+  stage: deploy
+  tags:
+    - docker
+  script:
+    - TARGET_IMAGE=$CI_REGISTRY_IMAGE:$CI_COMMIT_TAG
+    - SOURCE_IMAGE=$CONTAINER_TEST_IMAGE
+    - docker pull $SOURCE_IMAGE
+    - docker tag $SOURCE_IMAGE $TARGET_IMAGE
+    - docker push $TARGET_IMAGE
+  only:
+    - tags

.npmignore

+/install-npm.sh
+.git*
+/data
+/output
+/config.yaml
+.idea
+.dockerignore
+Dockerfile
\ No newline at end of file

.prettierrc

+{
+  "singleQuote": true,
+  "trailingComma": "all"
+}
\ No newline at end of file

LICENSE

+MIT License
+
+Copyright (c) 2019-present Shigma
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

 # typed-reflector
 
-`reflect-metadata` with typing support.
\ No newline at end of file
+Metadata reflector with typing support.
+
+## API
+
+### Type Map
+
+Either Reflector or Metadata Setter accepts 2 type arguments. The first one is the type map of common types, while the second one is the type map of arrays.
+
+### Reflector
+
+* `Reflector.get(metadataKey, instance, key)` Fetches the metadata of instance.
+
+* `Reflector.getArray(metadataKey, instance, key)` Fetches the array metadata of instance. Will return empty array if not exists.
+
+* `Reflector.getProperty(metadataKey, instance, key, alternate = instance)` Fetches the array metadata of instance from both class and property. The last parameter is an alternate source object for fetching metadata from class.
+
+### Metadata Setter
+
+* `Metadata.set(metadataKey, value)` Sets and overrides the metadata.
+
+* `Metadata.append(metadataKey, value)` Append to the the metadata array. The array would be created if not exists.
+
+* `Metadata.appendUnique(metadataKey, value)` Same as above but no duplicate values.
+
+* `Metadata.concat(metadataKey, value)` The value must be an array, and the metadata array would be joined together.
+
+

install-npm.sh

+#!/bin/bash
+
+npm install --save-dev \
+	@types/node \
+	typescript \
+	'@typescript-eslint/eslint-plugin@^4.28.2' \
+	'@typescript-eslint/parser@^4.28.2 '\
+	'eslint@^7.30.0' \
+	'eslint-config-prettier@^8.3.0' \
+	'eslint-plugin-prettier@^3.4.0' \
+	prettier

package-lock.json

+{
+  "name": "typed-reflector",
+  "version": "1.0.0",
+  "lockfileVersion": 2,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "typed-reflector",
+      "version": "1.0.0",
+      "license": "MIT",
+      "dependencies": {
+        "reflect-metadata": "^0.1.13"
+      }
+    },
+    "node_modules/reflect-metadata": {
+      "version": "0.1.13",
+      "resolved": "https://registry.npmjs.org/reflect-metadata/-/reflect-metadata-0.1.13.tgz",
+      "integrity": "sha512-Ts1Y/anZELhSsjMcU605fU9RE4Oi3p5ORujwbIKXfWa+0Zxs510Qrmrce5/Jowq3cHSZSJqBjypxmHarc+vEWg=="
+    }
+  },
+  "dependencies": {
+    "reflect-metadata": {
+      "version": "0.1.13",
+      "resolved": "https://registry.npmjs.org/reflect-metadata/-/reflect-metadata-0.1.13.tgz",
+      "integrity": "sha512-Ts1Y/anZELhSsjMcU605fU9RE4Oi3p5ORujwbIKXfWa+0Zxs510Qrmrce5/Jowq3cHSZSJqBjypxmHarc+vEWg=="
+    }
+  }
+}

package.json

+{
+  "name": "typed-reflector",
+  "version": "1.0.0",
+  "description": "Metadata reflector with typing support.",
+  "main": "dist/index.js",
+  "typings": "dist/index.d.ts",
+  "scripts": {
+    "lint": "eslint --fix .",
+    "build": "tsc"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://code.mycard.moe/3rdeye/typed-reflector.git"
+  },
+  "bugs": {
+    "url": "https://code.mycard.moe/3rdeye/typed-reflector/issues"
+  },
+  "homepage": "https://code.mycard.moe/3rdeye/typed-reflector",
+  "keywords": [
+    "reflect",
+    "reflector",
+    "reflect-metadata"
+  ],
+  "author": "Nanahira <nanahira@momobako.com>",
+  "license": "MIT",
+  "dependencies": {
+    "reflect-metadata": "^0.1.13"
+  }
+}

src/def/index.ts

+export * from './interfaces';

src/def/interfaces.ts

+export type StringDict = Record<string, any>;
+
+export type Key<T> = keyof T & string;
+
+export type ArrayValueMap<AM extends StringDict> = {
+  [K in keyof AM]: AM[K][];
+};
+
+export type ArrayValue<
+  AM extends StringDict,
+  K extends Key<ArrayValueMap<AM>>
+> = ArrayValueMap<AM>[K];
+
+export type MergeKey<M extends StringDict, AM extends StringDict> =
+  | Key<M>
+  | Key<AM>;
+
+export type GenericMap<M extends StringDict, AM extends StringDict> = M &
+  ArrayValueMap<AM>;
+
+export type MapValue<
+  M extends StringDict,
+  AM extends StringDict,
+  K extends MergeKey<M, AM>
+> = K extends Key<AM> ? ArrayValue<AM, K> : K extends Key<M> ? M[K] : never;

src/index.ts

+export * from './reflector';
+export * from './setter';
+export * from './def';

src/reflector.ts

+import 'reflect-metadata';
+import { ArrayValue, GenericMap, Key, MapValue, StringDict } from './def';
+
+export class Reflector<M extends StringDict, AM extends StringDict> {
+  get<K extends Key<GenericMap<M, AM>>>(
+    metadataKey: K,
+    instance: any,
+    key?: string | symbol,
+  ): MapValue<M, AM, K> {
+    const instanceClass = instance.constructor;
+    if (key) {
+      return Reflect.getMetadata(metadataKey, instanceClass, key);
+    } else {
+      return Reflect.getMetadata(metadataKey, instanceClass);
+    }
+  }
+
+  getArray<K extends Key<M>>(
+    metadataKey: K,
+    instance: any,
+    key?: string | symbol,
+  ): ArrayValue<AM, K> {
+    return this.get(metadataKey, instance, key) || [];
+  }
+
+  getProperty<K extends Key<M>, I = any>(
+    metadataKey: K,
+    instance: I,
+    key: keyof I & (string | symbol),
+    alternate: any = instance,
+  ): ArrayValue<AM, K> {
+    const valueFromClass = this.getArray(metadataKey, alternate);
+    const valueFromProperty = this.getArray(metadataKey, instance, key);
+    return [...valueFromClass, ...valueFromProperty] as ArrayValue<AM, K>;
+  }
+}

src/setter.ts

+import 'reflect-metadata';
+import { ArrayValueMap, GenericMap, Key, MergeKey, StringDict } from './def';
+
+export type AllDecorators = MethodDecorator &
+  ClassDecorator &
+  PropertyDecorator;
+
+export class Metadata<M extends StringDict, AM extends StringDict> {
+  private getMetadataInDecorator<
+    K extends MergeKey<M, AM>,
+    GM extends Record<MergeKey<M, AM>, any> = GenericMap<M, AM>
+  >(metaKey: K, target: any, key?: any): GM[K] {
+    const targetClass = target.constructor;
+    if (key) {
+      return Reflect.getMetadata(metaKey, targetClass, key);
+    } else {
+      return Reflect.getMetadata(metaKey, targetClass);
+    }
+  }
+
+  private setMetadataInDecorator<
+    K extends MergeKey<M, AM>,
+    GM extends Record<MergeKey<M, AM>, any> = GenericMap<M, AM>
+  >(metaKey: K, value: GM[K], target: any, key?: any) {
+    const targetClass = target.constructor;
+    if (key) {
+      return Reflect.defineMetadata(metaKey, value, targetClass, key);
+    } else {
+      return Reflect.defineMetadata(metaKey, value, targetClass);
+    }
+  }
+
+  transform<
+    K extends MergeKey<M, AM>,
+    IK extends Key<AM>,
+    GM extends Record<MergeKey<M, AM>, any> = GenericMap<M, AM>
+  >(
+    metadataKey: K,
+    metadataValueFun: (oldValue: GM[K]) => GM[K],
+    keysIndexMeta?: IK,
+  ): AllDecorators {
+    return (target: any, key?: any, descriptor?: any) => {
+      const oldValue = this.getMetadataInDecorator<K, GM>(
+        metadataKey,
+        target,
+        key,
+      );
+      const newValue = metadataValueFun(oldValue);
+      this.setMetadataInDecorator(metadataKey, newValue, target, key);
+      if (keysIndexMeta) {
+        const keysDec = this.append<IK, any>(keysIndexMeta, key);
+        keysDec(target);
+      }
+      if (descriptor) {
+        return descriptor;
+      }
+      return target;
+    };
+  }
+
+  set<K extends MergeKey<M, AM>, IK extends Key<AM>>(
+    metadataKey: K,
+    metadataValue: GenericMap<M, AM>[K],
+    keysIndexMeta?: IK,
+  ) {
+    return this.transform<K, IK>(
+      metadataKey,
+      () => metadataValue,
+      keysIndexMeta,
+    );
+  }
+
+  append<K extends Key<AM>, IK extends Key<AM>>(
+    metadataKey: K,
+    metadataValue: AM[K],
+    keysIndexMeta?: IK,
+  ) {
+    return this.transform<K, IK, ArrayValueMap<AM>>(
+      metadataKey,
+      (arr) => {
+        const newArr = arr || [];
+        newArr.push(metadataValue);
+        return newArr;
+      },
+      keysIndexMeta,
+    );
+  }
+
+  appendUnique<K extends Key<AM>, IK extends Key<AM>>(
+    metadataKey: K,
+    metadataValue: AM[K],
+    keysIndexMeta?: IK,
+  ) {
+    return this.transform<K, IK, ArrayValueMap<AM>>(
+      metadataKey,
+      (arr) => {
+        const newArr = arr || [];
+        if (newArr.includes(metadataValue)) {
+          return newArr;
+        }
+        newArr.push(metadataValue);
+        return newArr;
+      },
+      keysIndexMeta,
+    );
+  }
+
+  concat<K extends Key<AM>, IK extends Key<AM>>(
+    metadataKey: K,
+    metadataValue: ArrayValueMap<AM>[K],
+    keysIndexMeta?: IK,
+  ) {
+    return this.transform<K, IK, ArrayValueMap<AM>>(
+      metadataKey,
+      (arr) => (arr || []).concat(metadataValue),
+      keysIndexMeta,
+    );
+  }
+}

tsconfig.json

+{
+	"compilerOptions": {
+		"outDir": "dist",
+		"module": "commonjs",
+		"target": "es2020",
+		"esModuleInterop": true,
+		"emitDecoratorMetadata": true,
+		"experimentalDecorators": true,
+		"declaration": true,
+		"sourceMap": true
+	},
+	"compileOnSave": true,
+	"allowJs": true,
+	"include": [
+		"*.ts",
+		"src/**/*.ts",
+		"test/**/*.ts"
+	]
+}