When the callback function is executed for an element, the elements value and index will be passed to it and this information is logged. forEach () The syntax is fairly simple array.forEach (function(currentValue, index, arr), thisValue) The 1 st parameter is a ‘Required’ one and is a callback function that runs for each element of the array. Here, we use the required parameter of the callback function which is the value and an optional parameter which is the index. The code below logs the elements in the array colors along with each element's index. Notice how the v-for value matches the function signature of the forEach callback. function addTwoNumbers(num1, num2) Example 2: Log the elements of an array along with their index The v-for directive requires a special syntax in the form of item in. This is because, in Apps Script (which is a version of JavaScript), a function is basically a variable with a value of type function.Ĭonsider the function addTwoNumbers() below. Loops.Notice that there is no name for the function in the above example. In this implementation, we will create a simple Array of Objects in the Javascript file of Lightning Web Component and loop through it in multiple ways in LWC and Javascript. It consists of three parts, separated with a semicolon. You can then iterate over each key in the object using forEach(). Using Object.keys() The Object.keys() function returns an array of the object's own enumerable properties. So let’s just hop into the implementation. JavaScript for loops are similar to Java and C language for loops. But you can iterate over a JavaScript object using forEach() if you transform the object into an array first, using Object.keys(), Object.values(), or Object.entries(). JavaScript Loops Loops are handy, if you want to run the same code over and over again, each time with a different value.

You can choose from multiple ways to loop through List. This is extremely useful especially in Javascript when you need to loop through the list to perform some operation. for/in - loops through the properties of an object. In this post, we will implement different ways to loop through List in LWC and Javascript. JavaScript supports different kinds of loops: for - loops through a block of code a number of times. JavaScript has powerful semantics for looping through arrays and array-like objects.

Javascript for each syntax