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Example: Node 14 didn't support ECMAScript module. So now Node 16 supports them. import * as fs from "fs" // Let's use an ECMA Script Before (Node 14): const fs = require('fs') Take Aways: Use node 16 Use ES imports instead of commonjs imports import * as fs from ‘fs’ ----- const fs = require(‘fs’)

The promise will always log pending as long as its results are not resolved yet. You must call .then on the promise to capture the results regardless of the promise state (resolved or still pending): let AuthUser = function(data) { return google.login(data.username, data.password).then(token => { return token } ) } let userToken = AuthUser(data) console.log(userToken) // Promise { } userToken.th..

Javascript Scheduling: setTimeout and setInterval A block of JavaScript code is generally executed synchronously. But there are some JavaScript native functions (timers) which allow us to delay the execution of arbitrary instructions. setTimeout() setInterval() These let you run a piece of JavaScript code at some point in the future. That’s called “scheduling a call”. In this tutorial I’ll expla..

Strict inequality (!==) The strict inequality operator (!==) checks whether its two operands are not equal, returning a Boolean result. Unlike the inequality operator, the strict inequality operator always considers operands of different types to be different. Syntax x !== y Copy to Clipboard Description The strict inequality operator checks whether its operands are not equal. It is the negation..

Map The Map object holds key-value pairs and remembers the original insertion order of the keys. Any value (both objects and primitive values) may be used as either a key or a value. Description A Map object iterates its elements in insertion order — a for...of loop returns an array of [key, value] for each iteration. Key equality Key equality is based on the sameValueZero algorithm. NaN is cons..

! is the logical negation or "not" operator. !! is ! twice. It's a way of casting a "truthy" or "falsy" value to true or false, respectively. Given a boolean, ! will negate the value, i.e. !true yields false and vice versa. Given something other than a boolean, the value will first be converted to a boolean and then negated. For example, !undefined will first convert undefined to false and then ..

RegExp The RegExp object is used for matching text with a pattern. For an introduction to regular expressions, read the Regular Expressions chapter in the JavaScript Guide. Description Literal notation and constructor There are two ways to create a RegExp object: a literal notation and a constructor. The literal notation's parameters are enclosed between slashes and do not use quotation marks. T..

Promise.resolve() The Promise.resolve() method returns a Promise object that is resolved with a given value. If the value is a promise, that promise is returned; if the value is a thenable (i.e. has a "then" method), the returned promise will "follow" that thenable, adopting its eventual state; otherwise the returned promise will be fulfilled with the value. This function flattens nested layers ..

With the dramatic rise of functional programming in mainstream JavaScript, curried functions have become common in many applications. It’s important to understand what they are, how they work, and how to put them to good use. What is a curried function? A curried function is a function that takes multiple arguments one at a time. Given a function with 3 parameters, the curried version will take ..

Rest parameters The rest parameter syntax allows a function to accept an indefinite number of arguments as an array, providing a way to represent variadic functions in JavaScript. Syntax function f(a, b, ...theArgs) { // ... } Copy to Clipboard Description A function definition's last parameter can be prefixed with "..." (three U+002E FULL STOP characters), which will cause all remaining (user s..