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The JavaScript Cookbook

Updated Apr 29 2019

Note: this is a living document. Over time this post will fill up with tons of useful how-tos

Strings

• How to uppercase the first letter of a string in JavaScript
• How to check if a string contains a substring in JavaScript
• How to replace all occurrences of a string in JavaScript
• How to convert a string to a number in JavaScript
• How to create a multiline string in JavaScript
• How to check if a string starts with another in JavaScript

Numbers

• How to trim the leading zero in a number in JavaScript
• How to format a number as a currency value in JavaScript
• How to generate a random number between two numbers in JavaScript

Dates

• How to get the current timestamp in JavaScript

Objects

• How to remove a property from a JavaScript object
• How to inspect a JavaScript object
• How to deep clone a JavaScript object
• How to check if a JavaScript object property is undefined
• How to merge two objects in JavaScript
• How to access a method of an object dynamically in JavaScript
• How to use the destructuring syntax to work with arrays and objects in JavaScript
• How to count the number of properties in a JavaScript object
• How to list all methods of an object in JavaScript

Arrays

• How to remove an item from an Array in JavaScript
• How to append an item to an array in JavaScript
• How to initialize a new array with values in JavaScript
• How to use Async and Await with Array.map()
• How to empty a JavaScript array
• How to sort an array of objects by a property value in JavaScript
• How to get the unique properties of a set of objects in a JavaScript array

Functions

• How to set default parameter values in JavaScript

Loops

• How to get the index of an iteration in a for-of loop in JavaScript

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