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Quick tip about TypeScript and why to avoid these types

necraidan profile image Benjamin🦸‍♂️Auzanneau™ Updated on ・1 min read

Avoid the non-primitive Number, String, Boolean, Object, and Symbol types in TypeScript.
All of them refer to non-primitive reference types.
Instead, prefer the corresponding primitive types.

let textToCheck: String = 'text';
console.log(typeof textToCheck); // 'string'
console.log(textToCheck === 'text'); // true

textToCheck = new String('text');
console.log(typeof textToCheck); // 'object'
console.log(textToCheck === 'text'); // false

It's easy to failed your equality check with them.

There is also a performance part that I will not detail here. I recommend this article from mozilla which makes a performance comparison between a literal string and its object version in JavaScript.

That's it, make good use of it !


I'm not a native English speaker so, thanks in advance if you want to improve my article with correct syntax/grammar/sentences.

I can accept all kind remarks :)

Cover by JC Dela Cuesta on Unsplash

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necraidan profile

Benjamin🦸‍♂️Auzanneau™

@necraidan

Developer / Front-end enthusiast / JavaScript Hero. 🏀🏒🍻🇨🇦🐿️🇫🇷🦸‍♂️

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