@poppinss/utils - npm Package Compare versions

Comparing version 2.5.9 to 2.5.10

build/index.d.ts

 export { base64 } from './src/base64';
+export { compose, NormalizeConstructor } from './src/compose';
 export * as lodash from './src/lodash';
@@ -3,0 +4,0 @@ export { Exception } from './src/Exception';

build/index.js

@@ -30,5 +30,7 @@ "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.ManagerConfigValidator = exports.defineStaticProperty = exports.MessageBuilder = exports.randomString = exports.resolveFrom = exports.esmResolver = exports.interpolate = exports.esmRequire = exports.requireAll = exports.resolveDir = exports.fsReadAll = exports.safeStringify = exports.safeParse = exports.safeEqual = exports.Exception = exports.lodash = exports.base64 = void 0;
+exports.ManagerConfigValidator = exports.defineStaticProperty = exports.MessageBuilder = exports.randomString = exports.resolveFrom = exports.esmResolver = exports.interpolate = exports.esmRequire = exports.requireAll = exports.resolveDir = exports.fsReadAll = exports.safeStringify = exports.safeParse = exports.safeEqual = exports.Exception = exports.lodash = exports.compose = exports.base64 = void 0;
 var base64_1 = require("./src/base64");
 Object.defineProperty(exports, "base64", { enumerable: true, get: function () { return base64_1.base64; } });
+var compose_1 = require("./src/compose");
+Object.defineProperty(exports, "compose", { enumerable: true, get: function () { return compose_1.compose; } });
 // @ts-ignore
@@ -35,0 +37,0 @@ exports.lodash = __importStar(require("./src/lodash"));

package.json

 {
 	"name": "@poppinss/utils",
-	"version": "2.5.9",
+	"version": "2.5.10",
 	"description": "Handy utilities for repetitive work",
@@ -34,23 +34,23 @@ "main": "build/index.js",
 		"@adonisjs/mrm-preset": "^2.4.0",
-		"@adonisjs/require-ts": "^1.1.0",
+		"@adonisjs/require-ts": "^1.1.1",
 		"@poppinss/dev-utils": "^1.0.11",
 		"@types/ms": "^0.7.31",
-		"@types/node": "^14.14.8",
-		"commitizen": "^4.2.2",
+		"@types/node": "^14.14.22",
+		"commitizen": "^4.2.3",
 		"cz-conventional-changelog": "^3.3.0",
 		"del-cli": "^3.0.1",
-		"doctoc": "^1.4.0",
-		"eslint": "^7.13.0",
-		"eslint-config-prettier": "^6.15.0",
+		"doctoc": "^2.0.0",
+		"eslint": "^7.18.0",
+		"eslint-config-prettier": "^7.2.0",
 		"eslint-plugin-adonis": "^1.0.15",
-		"eslint-plugin-prettier": "^3.1.4",
+		"eslint-plugin-prettier": "^3.3.1",
 		"github-label-sync": "^2.0.0",
-		"husky": "^4.3.0",
+		"husky": "^4.3.8",
 		"japa": "^3.1.1",
 		"lodash-cli": "^4.17.5",
-		"mrm": "^2.5.12",
-		"np": "^7.0.0",
+		"mrm": "^2.5.13",
+		"np": "^7.2.0",
 		"npm-audit-html": "^1.5.0",
-		"prettier": "^2.1.2",
-		"typescript": "^4.0.5"
+		"prettier": "^2.2.1",
+		"typescript": "^4.1.3"
 	},
@@ -85,3 +85,3 @@ "nyc": {
 		"klona": "^2.0.4",
-		"ms": "^2.1.2",
+		"ms": "^2.1.3",
 		"require-all": "^3.0.0",
@@ -88,0 +88,0 @@ "resolve-from": "^5.0.0"

README.md

@@ -37,2 +37,4 @@ <div align="center"><img src="https://res.cloudinary.com/adonisjs/image/upload/q_100/v1557762307/poppinss_iftxlt.jpg" width="600px"></div>
 - [defineStaticProperty](#definestaticproperty)
+- [compose](#compose)
+  - [Mixins gotchas](#mixins-gotchas)
 
@@ -348,2 +350,3 @@ <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 ## defineStaticProperty
+
 Explicitly define static properties on a class by checking for `hasOwnProperty`. In case of inheritance, the properties from the parent class are cloned vs following the prototypal inheritance.
@@ -401,2 +404,82 @@
 
+## compose
+
+Javascript doesn't have a concept of inherting multiple classes together and neither does Typescript. However, the [official documentation](https://www.typescriptlang.org/docs/handbook/mixins.html) of Typescript does talks about the concept of mixins.
+
+As per the Typescript docs, you can create and apply mixins as follows.
+
+```ts
+type Constructor = new (...args: any[]) => any
+
+const UserWithEmail = <T extends Constructor>(superclass: T) => {
+  return class extends superclass {
+    public email: string
+  }
+}
+
+const UserWithPassword = <T extends Constructor>(superclass: T) => {
+  return class extends superclass {
+    public password: string
+  }
+}
+
+class BaseModel {}
+class User extends UserWithPassword(UserWithEmail(BaseModel)) {}
+```
+
+Mixins are close to perfect way of inherting multiple classes. I recommend reading [this article](https://justinfagnani.com/2015/12/21/real-mixins-with-javascript-classes/) for same.
+
+However, the syntax of applying multiple mixins is kind of ugly, as you have apply mixins over mixins creating a nested hierarchy as shown below.
+
+```ts
+UserWithAttributes(UserWithAge(UserWithPassword(UserWithEmail(BaseModel))))
+```
+
+The `compose` method is a small utility to improve the syntax a bit.
+
+```ts
+import { compose } from '@poppinss/utils'
+
+class User extends compose(
+  BaseModel,
+  UserWithPassword,
+  UserWithEmail,
+  UserWithAge,
+  UserWithAttributes
+) {}
+```
+
+### Mixins gotchas
+
+Typescript has an [open issue](https://github.com/microsoft/TypeScript/issues/37142) related to the constructor arguments of the mixin class or the base class.
+
+Typescript expects all classes used in the mixin chain to have a constructor with only one argument of `...args: any[]`. For example: The following code will work fine at runtime, but the **typescript compiler complains about it**.
+
+```ts
+class BaseModel {
+  constructor(name: string) {}
+}
+
+const UserWithEmail = <T extends typeof BaseModel>(superclass: T) => {
+  return class extends superclass {
+    // ERROR: A mixin class must have a constructor with a single rest parameter of type 'any[]'.ts(2545)
+    public email: string
+  }
+}
+
+class User extends compose(BaseModel, UserWithEmail) {}
+```
+
+You can work around this by overriding the constructor of the base class.
+
+```ts
+import { NormalizeConstructor, compose } from '@poppinss/utils'
+
+const UserWithEmail = <T extends NormalizeConstructor<typeof BaseModel>>(superclass: T) => {
+  return class extends superclass {
+    public email: string
+  }
+}
+```
+
 [circleci-image]: https://img.shields.io/circleci/project/github/poppinss/utils/master.svg?style=for-the-badge&logo=circleci
@@ -403,0 +486,0 @@ [circleci-url]: https://circleci.com/gh/poppinss/utils 'circleci'

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Found 1 instance in 1 package

Fixed alerts

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Improved metrics

Total package byte prevSize

79008

increased by5.99%

Number of package files

42

increased by5%

Lines of code

1119

increased by4.09%

Number of lines in readme file

492

increased by20.29%

Dependency changes

• Updatedms@^2.1.3