feat: use simpler reflect-metadata implementation (#315)

* remove core-js dependency in preset
* remove core-js import tests
* add small reflect metadata lib
* add test for relfect metadata lib
* update typescript version in preset to current

CHANGELOG.md

@@ -4,10 +4,10 @@
 * (**BREAKING**): Refine ast-transformer behavior: only transform `styles`-assignments inside @Component ([#261](https://github.com/thymikee/jest-preset-angular/pull/261)) and TypeScript v2.9 `createStringLiteral` is polyfilled if an older version is used ([#272](https://github.com/thymikee/jest-preset-angular/issues/272)).
 * (**BREAKING**): Restructure project with `src` and `build` folder ([#307](https://github.com/thymikee/jest-preset-angular/pull/307)).
 * (**BREAKING**): Support `tsconfig.spec.json` in root folder by default ([#309](https://github.com/thymikee/jest-preset-angular/pull/309)).
-* (**BREAKING**): Remove `core-js` peer dependency and instead add it as direct dependency ([#311](https://github.com/thymikee/jest-preset-angular/pull/309)).
+* Remove `core-js` dependency by using internal, minimal reflect-metadata ([#315](https://github.com/thymikee/jest-preset-angular/pull/315)). 
 
 #### Chore && Maintenance
-* Update example app to match Angular 8 Boilerplate ([#311](https://github.com/thymikee/jest-preset-angular/pull/309)).
+* Update example app to match Angular 8 Boilerplate ([#311](https://github.com/thymikee/jest-preset-angular/pull/311)).
 * Update example app to not use karma, extract jest config, fix paths ([#316](https://github.com/thymikee/jest-preset-angular/pull/316))
 
 #### Migration Guide

README.md

@@ -233,6 +233,15 @@ describe('Component snapshots', () => {
 
 Problems may arise if you're using custom builds (this preset is tailored for `angular-cli` as firstly priority). Please be advised that every entry in default configuration may be overridden to best suite your app's needs.
 
+### Can't resolve all parameters for SomeClass(?)
+
+This is related to Angular's reflection and also depends on a reflection library, as e. g. included in `core-js`. We use our own minimal reflection that satisfy Angular's current requirements, but in case these change, you can install `core-js` and import the reflection library in your `setupJest.ts`:
+```typescript
+require('core-js/es/reflect');
+require('core-js/proposals/reflect-metadata');
+```
+Note that this might also be related to other issues with the dependency injection and parameter type reflection.
+
 ### @Input() bindings are not reflected into fixture when `ChangeDetectionStrategy.OnPush` is used
 
 This issue is not related to Jest, [it's a known Angular bug](https://github.com/angular/angular/issues/12313)

example/yarn.lock

@@ -2437,7 +2437,7 @@ core-js-compat@^3.1.1:
     browserslist "^4.6.6"
     semver "^6.3.0"
 
-core-js@3.2.1, "core-js@>=2.0.0 < 4.0.0":
+core-js@3.2.1:
   version "3.2.1"
   resolved "https://registry.yarnpkg.com/core-js/-/core-js-3.2.1.tgz#cd41f38534da6cc59f7db050fe67307de9868b09"
   integrity sha512-Qa5XSVefSVPRxy2XfUC13WbvqkxhkwB3ve+pgCQveNgYzbM/UxZeu1dcOX/xr4UmfUd+muuvsaxilQzCyUurMw==
@@ -4519,7 +4519,6 @@ jest-mock@^24.0.0:
 "jest-preset-angular@file:..":
   version "7.1.1"
   dependencies:
-    core-js ">=2.0.0 < 4.0.0"
     jest-environment-jsdom-thirteen "^1.0.0"
     pretty-format "^24.0.0"
     ts-jest "^24.0.0"

package.json

@@ -8,7 +8,6 @@
   "author": "Michał Pierzchała <thymikee@gmail.com>",
   "license": "MIT",
   "dependencies": {
-    "core-js": ">=2.0.0 < 4.0.0",
     "jest-environment-jsdom-thirteen": "^1.0.0",
     "pretty-format": "^24.0.0",
     "ts-jest": "^24.0.0"
@@ -17,7 +16,7 @@
     "@types/jest": "^24.0.11",
     "@types/node": "^11.11.5",
     "jest": "^24.0.0",
-    "typescript": "^3.2.1"
+    "typescript": "^3.6.3"
   },
   "peerDependencies": {
     "@angular/core": ">=2.0.0",

src/__tests__/ReflectMetadata.test.ts

@@ -0,0 +1,22 @@
+import '../reflectMetadata';
+
+describe('using minimal reflect metadata', () => {
+
+  // to avoid type conflicts with global.Reflect comfortably
+  let reflect: any = Reflect;
+
+  it(`should make metadata() and getOwnMetadata() available on global.Reflect`, () => {
+    expect(typeof reflect.metadata).toBe('function')
+    expect(typeof reflect.getOwnMetadata).toBe('function')
+  });
+
+  it('should set and retrieve metadata using Reflect.metadata and Reflect.getOwnMetadata', () => {
+    const metadataValue = () => ({ test: 'object'});
+    const functionClass = function FunctionClass() {};
+
+    reflect.metadata('design:paramtypes', metadataValue)(functionClass);
+    const retrieved = reflect.getOwnMetadata('design:paramtypes', functionClass);
+    expect(retrieved).toBe(metadataValue);
+    expect(retrieved().test).toBe('object');
+  });
+});

src/reflectMetadata.ts

@@ -0,0 +1,23 @@
+const METADATA_KEY_PARAMTYPES = "design:paramtypes";
+const CTOR_PARAMETERS_JPA = "ctorParametersJPA";
+
+// weird workaround to avoid 'ReferenceError: globalThis is not defined' in node version < 11
+(global as any).globalThis = (global as any).globalThis || undefined
+
+const _global = globalThis || global; // globalThis available since node v12/TS v3.4
+const reflect: any = _global["Reflect"]; // reflect type in global has not these methods
+
+// let's not blindly override, maybe there is already a reflect lib in use
+// but just overriding one of the two functions does not serve any purpose
+if (!reflect.metadata && !reflect.getOwnMetadata) {
+  reflect.metadata = (metadataKey: any, metadataValue: any) => (target: any, key: any) => {
+    if (metadataKey === METADATA_KEY_PARAMTYPES && key === undefined) { // key undefined is ctor
+      target[CTOR_PARAMETERS_JPA] = metadataValue;
+    }
+  }
+  reflect.getOwnMetadata = (metadata: any, target: any, key: any) => {
+    if (metadata === METADATA_KEY_PARAMTYPES && key === undefined) { // key undefined is ctor
+      return target[CTOR_PARAMETERS_JPA];
+    }
+  }
+}

src/setupJest.ts

@@ -1,24 +1,6 @@
 'use strict';
 
-try {
-  require('core-js/es6/reflect');
-} catch (e) {
-  try {
-    require('core-js/es/reflect');
-  } catch(e) {
-    throw new Error('core-js es6-reflect not found!');
-  }
-}
-
-try {
-  require('core-js/es7/reflect');
-} catch (e) {
-  try {
-    require('core-js/proposals/reflect-metadata');
-  } catch (e) {
-    throw new Error('core-js es7-reflect not found!');
-  }
-}
+require('./reflectMetadata');
 
 require('zone.js/dist/zone.js');
 require('zone.js/dist/proxy.js');

yarn.lock

@@ -603,11 +603,6 @@ copy-descriptor@^0.1.0:
   resolved "https://registry.yarnpkg.com/copy-descriptor/-/copy-descriptor-0.1.1.tgz#676f6eb3c39997c2ee1ac3a924fd6124748f578d"
   integrity sha1-Z29us8OZl8LuGsOpJP1hJHSPV40=
 
-"core-js@>=2.0.0 < 4.0.0":
-  version "3.2.1"
-  resolved "https://registry.yarnpkg.com/core-js/-/core-js-3.2.1.tgz#cd41f38534da6cc59f7db050fe67307de9868b09"
-  integrity sha512-Qa5XSVefSVPRxy2XfUC13WbvqkxhkwB3ve+pgCQveNgYzbM/UxZeu1dcOX/xr4UmfUd+muuvsaxilQzCyUurMw==
-
 core-util-is@1.0.2, core-util-is@~1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.2.tgz#b5fd54220aa2bc5ab57aab7140c940754503c1a7"
@@ -3299,10 +3294,10 @@ type-check@~0.3.2:
   dependencies:
     prelude-ls "~1.1.2"
 
-typescript@^3.2.1:
-  version "3.3.3333"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.3.3333.tgz#171b2c5af66c59e9431199117a3bcadc66fdcfd6"
-  integrity sha512-JjSKsAfuHBE/fB2oZ8NxtRTk5iGcg6hkYXMnZ3Wc+b2RSqejEqTaem11mHASMnFilHrax3sLK0GDzcJrekZYLw==
+typescript@^3.6.3:
+  version "3.6.3"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.6.3.tgz#fea942fabb20f7e1ca7164ff626f1a9f3f70b4da"
+  integrity sha512-N7bceJL1CtRQ2RiG0AQME13ksR7DiuQh/QehubYcghzv20tnh+MQnQIuJddTmsbqYj+dztchykemz0zFzlvdQw==
 
 uglify-js@^3.1.4:
   version "3.6.0"