linter: add a new rule that disallows using this in an exported function #15359
Description
Description
It would be nice to have a rule that disallows using this in an exported function.
In most bundlers, the value of this is not preserved for exported functions.
// imported.js
export function method() {
// `this` is the module namespace object of `imported.js` here
// but in most bundlers, `this` becomes `undefined`
// (or even if it's a namespace object, some properties would be missing due to tree-shaking)
console.log(this);
}
// main.js
import * as namespace from './imported.js';
namespace.method();See esbuild's document for more details.
I didn't find any existing rule for this.
Examples
Examples of incorrect code for this rule:
export function foo() {
console.log(this) // warn this
this.something // warn this
const self = this // warn this
}Examples of correct code for this rule:
function foo() {
console.log(this)
this.something
}
export const bar = () => {
console.log(this)
this.something
}Category
I guess this should be suspicious. It is fine to use this unless it's bundled, so this should not be correctness.