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Type checking JavaScript

Dominic Myers on December 20, 2020

By Adam Drobiec I read an article yesterday by Gil Tayar, which was fascinating. In it, he talked about his journey from strongly typed language...
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Curtis Fenner •

What did you mean by TypeScript not being happy with checking for the existence of variables with !!? TypeScript is perfectly happy to do that:

const a: number | null = myFunction();
if (!!a) {
    const b: number = a; // typechecks
}
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I find myself far more productive in TypeScript because it lets me plan more (by writing types before the implementation, which often exposes silly things that I can fix before writing a lot of code) and generally be more hasty while still having confidence that my code is more or less correct. I use strict: true and rarely run into problems, especially because I can just use as in the uncommon cases that I can't convince the TypeScript compiler of something.