Docs: Extend a documentation on how casting works

[Hell4Ge]

Search Terms

• cast

Suggestion

A docs should clear how casting works since it's not like in any other language which I will explain later

Use Cases

• The docs

Examples

According to https://www.typescriptlang.org/play/

This code:

const someStringNumber: string = '100';
const someNumber: number = someStringNumber as unknown as number;

console.log(typeof someNumber); // string

converts into

"use strict";
const someStringNumber = '100';
const someNumber = someStringNumber;
console.log(typeof someNumber); // string

Which does not make any sense, it does nothing and makes weird bugs during runtime.

It's the same here:

let foo: string = "100";
let xyz: number = <number><unknown>foo;

This compiles into

var foo = "100";
var xyz = foo;

[MartinJohns]

Type assertions are often wrongly called casts, which can lead to a lot of confusion with people unfamiliar with the language.

Perhaps you should clarify what about the documentation should be extended, as it seems quite clear to me.

Type Assertions

Type assertions are a way to tell the compiler “trust me, I know what I’m doing.” A type assertion is like a type cast in other languages, but performs no special checking or restructuring of data. It has no runtime impact, and is used purely by the compiler. TypeScript assumes that you, the programmer, have performed any special checks that you need.

[RyanCavanaugh]

It seems like you're confused by the very thing the documentation specifically describes, so I'm not sure what else to do.