JavaScript Array

array in javascript

JavaScript Array is an object that represents a collection of similar type of elements.

Arrays store multiple values in a single variable.

There are 3 ways to construct array in JavaScript

  • By array literal
  • And By creating instance of Array directly (using new keyword)
  • And By using an Array constructor (using new keyword)

i) JavaScript array literal

As you can see, values are contained inside [ ] and separated by , (comma).

Example:

<script>

var emp=["Sonoo","Vimal","Ratan"];

for (i=0;i<emp.length;i++){

document.write(emp[i] + "<br/>");

}

</script>

ii) JavaScript Array directly (new keyword)

Here, new keyword is used to create instance of array.

Example:

<script>

var i;

var emp = new Array();

emp[0] = "Arun";

emp[1] = "Varun";

emp[2] = "John";



for (i=0;i<emp.length;i++){

document.write(emp[i] + "<br>");

}

</script>

iii) JavaScript array constructor (new keyword)

Here, you need to create instance of array by passing arguments in constructor so that we don’t have to provide value explicitly.

Example:

<script>

var emp=new Array("Jai","Vijay","Smith");

for (i=0;i<emp.length;i++){

document.write(emp[i] + "<br>");

}

</script>

Array Method’s

Let’s see the list of JavaScript array methods with their description.

  • concat() : It returns a new array object that contains two or more merged arrays.
  • copywithin() : It copies the part of the given array with its own elements and returns the modified array.
  • entries() : It creates an iterator object and a loop that iterates over each key/value pair.
  • every() : It determines whether all the elements of an array are satisfying the provided function conditions.
  • flat() : It creates a new array carrying sub-array elements concatenated recursively till the specified depth.
  • flatMap() : It maps all array elements via mapping function, then flattens the result into a new array.
  • fill() : It fills elements into an array with static values.
  • from() : It creates a new array carrying the exact copy of another array element.
  • filter() : It returns the new array containing the elements that pass the provided function conditions.
  • find() : It returns the value of the first element in the given array that satisfies the specified condition.
  • findIndex() : It returns the index value of the first element in the given array that satisfies the specified condition.
  • forEach() : It invokes the provided function once for each element of an array.
  • includes() : It checks whether the given array contains the specified element.
  • indexOf() : It searches the specified element in the given array and returns the index of the first match.
  • isArray() : It tests if the passed value is an array.
  • join() : It joins the elements of an array as a string.
  • keys() : It creates an iterator object that contains only the keys of the array, then loops through these keys.
  • lastIndexOf() : It searches the specified element in the given array and returns the index of the last match.
  • map() : It calls the specified function for every array element and returns the new array.
  • of() : It creates a new array from a variable number of arguments, holding any type of argument.
  • pop() : It removes and returns the last element of an array.
  • push() : It adds one or more elements to the end of an array.
  • reverse() : It reverses the elements of given array.
  • reduce(function, initial) : It executes a provided function for each value from left to right and reduces the array to a single value.
  • reduceRight() : It executes a provided function for each value from right to left and reduces the array to a single value.
  • some() : It determines if any element of the array passes the test of the implemented function.
  • shift() : It removes and returns the first element of an array.
  • slice() : It returns a new array containing the copy of the part of the given array.
  • sort() : It returns the element of the given array in a sorted order.
  • splice() : It add/remove elements to/from the given array.
  • toLocaleString() : It returns a string containing all the elements of a specified array.
  • toString() : It converts the elements of a specified array into string form, without affecting the original array.
  • unshift() : It adds one or more elements in the beginning of the given array.
  • values() : It creates a new iterator object carrying values for each index in the array.

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