Search Results for: javascript object

This tutorial will show you how to properly copy/clone an array or object in JavaScript – it’s not as simple as it seems! Copying an array or object may seem simple – but JavaScript throws a spanner in the works – the fact that when you assign the value of one variable to another it references the original variable. This means that if the value of the original variable is changed, the value of the copy will change too! To get around this, you will need to clone the array – ensuring … Read more

This article will show you the ways to convert an object to an array in JavaScript – quickly and easily. There are many ways to convert objects to arrays, but these (should) be the most straightforward methods. Converting Object to Array in JavaScript – Values Only If you only need the values from the object, the Object.values() method will extract them into an array: var myObject = { colour: ‘blue’, number: 43, name: ‘Fred’, enabled: true }; var values = Object.values(myObject); console.log(values); The above will return an array with … Read more

The Object.entries() method in JavaScript can be used to convert an object to an array – but it doesn’t work recursively. So here’s a function to accomplish that. I can’t think of a reason why you’d want to do this, but it came up while putting together an article on using Object.entries() – so here it is! Recursive Function for Converting Objects to Arrays I’ll let the comments do the talking as to what’s going on. The gist of it is that (for whatever reason) you want to convert an … Read more

The ‘this‘ keyword in JavaScript is a confusing concept for some – the meaning of ‘this‘ changes based on context.  This article explains what ‘this‘ is. What is Object-Oriented Programming Object-Oriented Programming is a way of structuring your code so that data is organized into objects. JavaScript supports Object-Oriented programming and provides various tools to help implement it. Put simply, rather than having a bunch of separate abstract variables describing an item, you combine them into a single object which represents that item. You can also add functions … Read more

This article will detail the various methods for including a JavaScript file in another JavaScript file – providing several methods for use in the browser, and when working in Node.js. One of the cornerstones of programming is reusable code. This concept is encapsulated in the DRY (Don’t Repeat Yourself) principle – that if you need to do something multiple times, you write the code for it once, and re-use it where it is required, rather than having multiple copies of the same code in your code base. … Read more

This article will explain and list JavaScript operators and expressions. JavaScript operators perform a given operation on the provided expressions or values. Common operations include comparisons, arithmetic, and ternary operations. You will use JavaScript operators frequently (even the simplest JavaScript code will use multiple operators!), so it’s worth getting to know them, and their expected behaviour. What are Operators and Operands? Javascript operators perform a given operation, for example addition, subtraction, and other arithmetic, comparisons like greater than/less than, and more complicated operations like ternary/comparison … Read more

This article will explain equality and inequality in the JavaScript Programming language, and provide code examples showing how to check if values are equal in value and type. Checking whether two values are equal can get a bit confusing in JavaScript – there is loose equality and strict equality involving types to consider. Read on to find out how testing for equality and inequality works in JavaScript. What are equality and inequality? In programming, equality is the process of checking whether two values are equal … Read more

This article will show you how to use the simplest JavaScript loop – the for loop, and provide code examples. JavaScript for Loops JavaScript’s for loops are used to execute a block of code repeatedly until a condition is met. The initial variables, condition that must be met, and the expression which progresses the loop are all defined within the loop expression. for loop Syntax JavaScript for loops follow the following syntax: for (INITIALIZATION; CONDITION; FINAL_EXPRESSION) { //Code to be executed in the loop } Note that: INITIALIZATION sets the variable which is used to control … Read more

This article will quickly explain nested for loops in JavaScript, how they are used with multidimensional arrays, and show some examples. For Loops We’ve already covered for loops – check out our article here. To sum up the article, for loops repeat a block of code for a given number of iterations: for (let i = 0; i <= 3; i++) { console.log(i); // Will output the numbers 0-3 to the console } Above, a for loop is defined that defines an initial variable i that is used to control the loop, sets a … Read more

This article will show you how to filter an array using multiple conditions, to return multiple values. Example code is provided. We’ve already covered filtering arrays in general – this article covers specifically how multiple conditions can be used with the Array.filter() method. The Array.filter() Method The filter() method is available on all arrays in JavaScript. It creates a new array, containing only the items from the original array which passes all conditions in a provided function. filter() Method Syntax The syntax for the array filter() method is as follows: ARRAY.filter(ELEMENT => FUNCTION) Note that: ARRAY is … Read more