What is “DefinitelyTyped”?

Question

I see \"DefinitelyTyped\" is something related to TypeScript/JavaScript development, but I couldn\'t understand its use or some code sample to understand about it.

I

Answer 1

The description above is quite clear, however, if you are like me, maybe the code below may help u get the big picture.

For example, you have lodash package in your project, you import and use a method of it.

import random from 'lodash/random';

const result = random(????);

You may stop and wonder how many parameters this method may require? and what kind of data for each parameter? You have to search for the lodash homepage, find the API documentation of random to know how to use it. After doing a bunch of tasks, you may end up providing wrong the order of parameters, but nothing will show until you run your app and get the error.

This is where DefinitelyType shows its power. After installing the DefinitelyType of lodash

yarn add @types/lodash

• when you start typing the random method, a tooltip will show and guide you how to use the parameters.
• when you provide wrong data type of parameters, it will show the error in order to let you know and fix it immediately.

Does it make sense? if not, don't worry, turn off the music and listen to this video, I'm sure you will understand it.