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How to Find the Length Of an Array In JavaScript?

4 minutes read

To find the length of an array in JavaScript, you can use the length property that is built into all arrays in JavaScript. This property will return the number of elements in the array, which is essentially the length of the array. For example, if you have an array named myArray, you can find its length by accessing myArray.length. This will give you the total number of elements in the array.

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What does the filter method do in JavaScript arrays?

The filter method creates a new array with all elements that pass a given test implemented by the provided function. It does not change the original array, but instead returns a new array with only the elements that meet the specified criteria.


How to merge two arrays in JavaScript?

There are several ways to merge two arrays in JavaScript.

  1. Using the concat() method:
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const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];

const mergedArray = arr1.concat(arr2);
console.log(mergedArray);


  1. Using the spread operator:
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const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];

const mergedArray = [...arr1, ...arr2];
console.log(mergedArray);


  1. Using the push() method:
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const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];

arr1.push(...arr2);
console.log(arr1);


  1. Using the Array.from() method:
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const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];

const mergedArray = Array.from(arr1).concat(arr2);
console.log(mergedArray);


Choose the method that best suits your coding style and requirements.


What is the difference between push and unshift methods in JavaScript arrays?

The main difference between the push and unshift methods in JavaScript arrays is where they add elements in the array.

  1. push: The push method adds one or more elements to the end of an array. It increases the length of the array by the number of elements added. Example:
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let arr = [1, 2, 3];
arr.push(4); // [1, 2, 3, 4]


  1. unshift: The unshift method adds one or more elements to the beginning of an array. It increases the length of the array by the number of elements added. Example:
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let arr = [2, 3, 4];
arr.unshift(1); // [1, 2, 3, 4]


In summary, push adds elements to the end of the array, while unshift adds elements to the beginning of the array.

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