Interactive javascript cheatsheet

execute javascript from the browser console

execute javascript from an inline <script> tag

execute an external javascript script from html

execute javascript outside the browser using Node.js

console.log()

comments

variables

alert

undefined and null

good references

introduction

+

template string

escape characters

.length

.split()

.substring()

.charAt()

.toLowerCase()

.toUpperCase()

introduction

arithmetic operations

increment and decrement assignment

from string

from boolean/undefined/null

parseInt()

parseFloat()

hexadecimal, binary and decimal exponential notations

.toString(): hexadecimal and binary representation strings

bitwise operations

NaN: Not-A-Number

.toLocaleString(): format a number separators (eg. decimal and thousand separators)

.toLocaleString(): format currency

introduction

comparison operators (==, ===, !=, !==, >, >=, <, <=)

logical operators (&&, ||, !)

if, else if and else

while loops

do while loops

introduction

access an array element

for loop: iterate over an array

.push(): add an item to the end of an array

.unshift(): add item to the start of an array

.pop(): remove last item

.shift(): remove first item

.slice(): get a slice of an array

.splice(): remove or replace existing elements and/or insert new ones

.filter(): create a filtered array

.map(): transform one array to another

.reduce(): iterate over array and accumulate over a value

.forEach(): iterate over elements of an array

.join(): join an array into a string

create an array filled with zeros

create an array filled with number from 0 to n-1

introduction

function which receives inputs

function returns returns a value

arrow functions

function references

higher order function

recursion

.call(): call a function with another `this`

.apply(): call a function with another `this`

.bind(): create a new function with a bound `this`

introduction

access an object's property

insert/modify an object's properties

remove an objects's property

method: a function property

this: reference other properties inside an method

Object.keys(): list an object's keys

Object.values(): list an object's values

Object.entries(): list an object's key-values pairs

prototype object

`new` keyword

introduction

getter and setter

class field

bind `this` to the instance object

inheritance

static methods/properties

private methods/properties

instanceof

introduction

from string

from year, month, day, hours, minutes and seconds

get year, month, day, weekday, hours, minutes, seconds, milliseconds and timestamp

from epoch timestamp

to formatted string

.toLocaleDateString(): more control over formatted string

to specific timezone

try...catch

throw

finally

custom errors

why we need them?

introduction

chaining

async/await

Promise.all()

Promise.allSettled()

error handling

introduction

combining generators

passing values to a generator

async generators