Use ES Module Syntax to Import Node.js Modules like fs or https

In Node.js each .js file is considered as a separate CommonJS module. That means if we declare a variable or function inside a file, we cannot access it from another file. We need to explicitly mention, what all variables and functions can be accessed by other files.

Import Core Node Modules in CommonJS Way

We know that Node.js comes with multiple modules like fs or https out of the box. If we need to use say, fs in our code, here is the syntax.

const fs = require("fs");

// Then use it like..
fs.readFileSync();

Import Core Node Modules in ES Module Way

If we are rewriting above code in ES Module way, it looks like this:

import * as fs from "fs";

fs.readFileSync();

Above syntax is one of the way in which we use import keyword. It takes all exported variables or functions from fs package and make it available for use.

Here are other ways we use import keyword.

import defaultExport from "module-name";
import * as name from "module-name";
import { export1 } from "module-name";
import { export1 as alias1 } from "module-name";
import { default as alias } from "module-name";
import { export1 , export2 } from "module-name";
import { export1 , export2 as alias2 , [...] } from "module-name";
import { "string name" as alias } from "module-name";
import defaultExport, { export1 [ , [...] ] } from "module-name";
import defaultExport, * as name from "module-name";
import "module-name";

You can read more in this MDN link.