Clash Royale CLAN TAG

TypeScript combining *.js + *.d.ts again?

TypeScript tsc -d "declaration" of "compilerOptions" generates corresponding '.d.ts' file.

tsc -d

For instance, from:

const log = (m: unknown) => {
console.log((m));
return m;
};


it generates:

const log = (m) => {
console.log((m));
return m;
};


and:

declare const log: (m: unknown) => unknown;


I think this is quite interesting because it "devides" the TypeScript source code to a native JavaScript code and the extra type definition.

Then, here is my thought. After deviding the native code and type definition, is it easily possilbe to generate a valid TypeScript code by re-binding both codes.

For instance:

declare const log1: (m: unknown) => unknown;

const log1 = m => {
console.log((m));
return m;
};


This code generates an errors:

[ts] Cannot redeclare block-scoped variable 'log1'.


for each statements.

Why am I tring this?

I'm motivated by facts:

In Algebra,

(x^2 + 3x +2) = (x+1)(x+2) = (x^2 + 3x +2)

I want to confirm if the same thing is valid under TypeScript.

The fact makes me think, in a sense, the output of the vanilla JS code is type safe and valid with TypeScirpt, just without the *.d.ts file which is eventually appearently merely an extra helper functionality that TypeScript compiler takes advantage of. It's just a tool.

Accordingly, the type-safty of the vanilla JS code can be later, easily validated by TypeScript compiler with the helper functional tool, that is tmp.d.ts. That is what I want to confirm.

tmp.d.ts

Thanks.

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