ESLint v8 now supports static class properties natively: https://eslint.org/blog/2021/10/eslint-v8.0.0-released parserOptions ecmaVersion should be set to 13, 2022, or “latest” to enable the support. Add this to your .eslint.(cjs | json | js) { parserOptions: { ecmaVersion: 2022, } }
Initializing properties directly on a class in ES6 is not possible, only methods can currently be declared in this way. Same rules stand in ES7 as well. However, it is a proposed feature that might come after ES7 (currently in stage 3). Here is the official proposal. Additionally, the syntax the proposal is suggesting is … Read more
It looks like it is a problem to hand over a string which has a special meaning. If really necessary, you evaluate a string. class Test { #field = ‘foo’; get field() { return eval(‘this.’ +’#field’); } } console.log(new Test().field)
Simply put, the reason to use this is ease of understanding the code. Without class field declarations, you would do something like: class Person { constructor() { this.firstName = “Mike”; this.lastName = “Patel”; this.getName = () => { return this.firstName + ” ” + this.lastName; }; } } var p = new Person(); console.log(p.firstName); // … Read more
If you want to use experimental features (such as arrows as class methods) you need to use babel-eslint as a parser. Default parser (Espree) doesn’t support experimental features.
There are differences between all 3 versions. This differences are in 3 areas: Who is this at runtime Where the function is assigned What is the type of this in typescript. Lets start with where they work just the same. Consider this class, with a class field: class Greeter { constructor(private x: string) { } … Read more
You make “public static field” using accessor and a “static” keyword: class Agent { static get CIRCLE() { return 1; } static get SQUARE() { return 2; } } Agent.CIRCLE; // 1 Looking at a spec, 14.5 — Class Definitions — you’d see something suspiciously relevant 🙂 ClassElement[Yield] : MethodDefinition[?Yield] static MethodDefinition[?Yield] ; So from … Read more
They are roughly equivalent. The significant difference is that the initializer in the second example is executed before constructor. The second approach uses class fields proposal. It is not a part of ECMAScript standard yet so you need to set up transpiler properly to use the second approach. UPD Take a look at Babel output … Read more
The feature you are using is not part of ES6. It’s the class fields proposal. It allows you to initialize instance properties without having to write a constructor. I.e. your code: class MyClass { myMethod = () => { this.myVariable++; } } is exactly the same as class MyClass { constructor() { this.myMethod = () … Read more
First: A simple solution will be to create a component for the content inside a map function and pass the values as props and when you call the function from the child component you can pass the value to the function passed down as props. Parent deleteTodo = (val) => { console.log(val) } todos.map(el => … Read more