Some signatures should use union instead of overloads

I think, this code should be correct code by fixes of lib.d.ts or type system.

var separator: string|RegExp;
'str'.split(separator); // type error

Manual: Replace to union types

Resolve by type definition.

from:

// lib.d.ts
    split(separator: string, limit?: number): string[];
    split(separator: RegExp, limit?: number): string[];

to:

// lib.d.ts
    split(separator: string|RegExp, limit?: number): string[];

Automatic: Generate union types

Resolve by auto generated merged signature from overloads.

from:

// lib.d.ts
    split(separator: string, limit?: number): string[];
    split(separator: RegExp, limit?: number): string[];

Generate the merged signature internally, implicitly.

to:

// in memory
    split(separator: string, limit?: number): string[];
    split(separator: RegExp, limit?: number): string[];
    split(separator: string|RegExp, limit?: number): string[]; // generated

Agreed, we should fix the declaration of split to take a union type for the first parameter.

Thanks! Should I create a list of all integration targets? Such as String#match/replace/search, and more many types. This is steady manual works.

It's probably worth having a script or something to find these cases.

Unfortunately we can't perform this merging on the type system side because the two forms (two overloads vs one overload with a union) actually have rather different semantics in practice.

All right, I'll leave it up to you.

When TypeScript fixes this issue? I want to fix this issue myself partially if TypeScript doesn't fix this issue until next version 1.8.

falsandtru (@falsandtru)

falsandtru (@falsandtru) feel free to send a PR for the issue.

Mohamed Hegazy (@mhegazy)

Mohamed Hegazy (@mhegazy) thanks, I'll fix it.

Join some overloads of string methods to union parameters

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Some signatures should use union instead of overloads #5766

Manual: Replace to union types

Automatic: Generate union types

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Some signatures should use union instead of overloads #5766

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Manual: Replace to union types

Automatic: Generate union types

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ahejlsberg commented on Nov 24, 2015

falsandtru commented on Nov 24, 2015

RyanCavanaugh commented on Nov 24, 2015

falsandtru commented on Nov 25, 2015

falsandtru commented on Jan 15, 2016

mhegazy commented on Jan 16, 2016

falsandtru commented on Jan 16, 2016

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