René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Order of constructor parameter properties vs class properties initializers - Discrepency between typescript and bable ","articleBody":"### 💻\n\n- [ ] Would you like to work on a fix?\n\n### How are you using Babel?\n\n@rollup/plugin-babel\n\n### Input code\n\nOriginal Code: \r\n\r\n```js\r\nclass Dashboard {\r\n    name = 'stats' + this.amount;\r\n\r\n    constructor(\r\n        readonly amount\r\n    ) { \r\n    }\r\n}\r\n```\r\n\r\nBabel Emit:\r\n\r\n```js\r\n\"use strict\";\r\n\r\nfunction _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }\r\n\r\nclass Dashboard {\r\n  constructor(amount) {\r\n    _defineProperty(this, \"name\", 'stats' + this.amount);\r\n\r\n    this.amount = amount;\r\n  }\r\n}\r\n```\r\n\r\nTypescript emits:\r\n\r\n```js\r\nclass Dashboard {\r\n    constructor(amount) {\r\n        this.amount = amount;\r\n        this.name = 'stats' + this.amount;\r\n    }\r\n}\r\n```\r\n\n\n### Configuration file name\n\nbabel.config.js\n\n### Configuration\n\nFor reproduction I've used the Babel online repl with Env stage 2 preset and Typescript preset. \r\n[link](https://babeljs.io/repl/#?browsers=defaults%2C%20not%20ie%2011%2C%20not%20ie_mob%2011&build=&builtIns=false&corejs=3.6&spec=false&loose=false&code_lz=MYGwhgzhAEAikAsBGB7MAnAJtA3gKGkOgDswBbAU2gF5oByCAFzEYjugGppGEBLCAHTkUAV2KMA3HgJFgKYk3QjgjFOgAUMokXQUwmeSACe0YWMZboASlzRLAXzz2gA&debug=false&forceAllTransforms=false&shippedProposals=false&circleciRepo=&evaluate=false&fileSize=false&timeTravel=false&sourceType=module&lineWrap=true&presets=env%2Creact%2Cstage-2%2Ctypescript&prettier=false&targets=&version=7.15.7&externalPlugins=&assumptions=%7B%7D)\r\n\r\nFor typescript reproduction I've used Typescript playground.\r\n[link](https://www.typescriptlang.org/play?ssl=9&ssc=2&pln=1&pc=1#code/MYGwhgzhAEAikAsBGB7MAnAJtA3gKGkOgDswBbAU2gF5oByCAFzEYjugGppGEBLCAHTkUAV2KMA3HgJFgKYk3QjgjFOgAUMokXQUwmeSACe0YWMYAuEiLJIK6ADRboASlzTtAXzyegA)\n\n### Current and expected behavior\n\nCurrent Behavior - Babel puts parameter properties in the constructor after class properties assignment. Typescript puts them before.\r\n\r\nExpected Behavior - Its a discrepancy. Not sure if Babel is the responsible or Typescript. Typescript behavior is more preferable to me because it makes writing shorter for me.\n\n### Environment\n\n- Babel - 7.15.7\r\n- Typescript - 4.4.2\n\n### Possible solution\n\nNot sure. I've found some issues talking about plugin orders but I'm not sure.\n\n### Additional context\n\n_No response_","author":{"url":"https://github.com/elpddev","@type":"Person","name":"elpddev"},"datePublished":"2021-09-21T09:30:24Z","url":"https://github.com/babel/babel/issues/13779"}