Enhance the efficiency of writing the *.d.ts file

I have recently started diving into TypeScript with React and encountered a new concept called a .d.ts file. I am wondering if there is an established best practice for writing this file or if it's more of a developer preference. Can someone verify if my approach to writing the .d.ts file is correct? My goal is to utilize the enquireScreen function in TypeScript. Thank you! 😊

Below is the JSX code snippet:

let enquireJs;
if (typeof window !== 'undefined') {
  const matchMediaPolyfill = mediaQuery => {
    return {
      media: mediaQuery,
      matches: false,
      addListener() {
      },
      removeListener() {
      },
    };
  };
  window.matchMedia = window.matchMedia || matchMediaPolyfill;
  enquireJs = require('enquire.js');
}

const mobileQuery = 'only screen and (max-width: 767.99px)';

export function enquireScreen(cb, query = mobileQuery) {
  if (!enquireJs) {
    return;
  }

  const handler = {
    match: () => {
      cb && cb(true);
    },
    unmatch: () => {
      cb && cb();
    },
  };
  enquireJs.register(query, handler);
  return handler;
} 

This is how I structured my own .d.ts file:

import enquireJS = require('enquire.js');

export const mobileQuery = 'only screen and (max-width: 767.99px)';

export function enquireScreen(cb: any, query = mobileQuery);

Answer â„–1

.d.ts files serve as declaration files that exclusively contain type information and do not generate .js outputs. They are utilized solely for type checking purposes. TypeScript automatically identifies type definitions located in node_modules/@types, eliminating the need for any additional steps to make these types accessible in your application.

Alternatively, you have the option to establish your own types directory within tsconfig under "typeRoots": ["./typings"] or within include. For instance, you can define a type declaration in a d.ts file as well.

declare type status = 'PENDING' | 'ACTIVE'

If the path to this d.ts file is outlined in tsconfig, this type will be usable throughout your TypeScript application.

Your d.ts code might appear like this:

declare const mobileQuery = 'only screen and (max-width: 767.99px)';
declare function enquireScreen(cb: any, query = mobileQuery);

This file path could then be included in your tsconfig according to the instructions provided above.

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