Improve string split return type of first array index

lib Update Request

Please, consider improving user experience for "".split(...) in cases when string literal is passed, which I believe most users do e.g. split(' ') or split('\n')

Configuration Check

My compilation target is ES2015 and my lib is the default.

Missing / Incorrect Definition

https://github.com/microsoft/TypeScript/blob/b70784ef8f3ba3fd21750b9acf275dd7edcc7fe7/src/lib/es5.d.ts#L460

Essentially duplicate of https://github.com/microsoft/TypeScript/issues/49635, but with https://github.com/microsoft/TypeScript/issues/49635#issuecomment-1163047914 handled:

split<T extends string | RegExp>(separator: T, limit?: number): T extends `${string}${infer U}` ? [string, ...string[]] : string[];

And this should added to param JSDoc then: Only passing `""` and `new RegExp("")` values can result in returning an empty array.

Sample Code

This is super inconvenient when used with destructure:

const [firstLine, ...restLine] = str.split('\n')
// firstLine is possibly undefined, need add exclamation marks everywhere or `as [string, ...string]` above

I also wanted to do the same for when regexp literal is passed e.g. split(/\n\r?/) as only split(new RegExp('')) can result in empty array (if I'm not mistaken), which I believe no one does, but the literal value can't be captured anyway

Documentation Link

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split#description (note)

P.S. I remembered of this issue after https://github.com/microsoft/TypeScript/pull/49682, which significantly improved type-checking experience by using less exclamation marks

Commencez par la déclaration de String.split dans src/lib/es5.d.ts vers la ligne 460, puis examinez l’issue associée #49635 et le commentaire auquel elle fait référence. Le travail est terminé lorsque le type distingue les séparateurs littéraux non vides comme renvoyant un tuple dont le premier élément est non vide, tout en conservant les cas de tableaux vides et en documentant ces cas dans le JSDoc du paramètre.