In JavaScript, an array is a collection of data that can be of the same or different type. If we have the array containing the data, our task is to identify if it is a string data type. In this article, we will learn how to use the typeof operator.
Syntax:
typeof value
Note: The typeof operator returns a string indicating the type of the operand.
Example 1:
Input:
const sample = “neveropen”;
console.log(typeof sample);Output : string
Example 2:
Input:
const sample = 369;
console.log(typeof sample);Output : number
Example 3:
Input:
const sample = true;
console.log(typeof sample);Output : boolean
Approach:
- Iterate over the whole array to check if each element is a string or we will do it using for loop.
- We will compare the type of iterator element with the ‘string’ data type using the if block.
- If block will execute if it encounters the string data type.
- When there is no string value present, else block will get executed.
Example 1: The following code demonstrates the case where the string is present.
Javascript
<script> // Declare the array const arr = [1,2,3,"Geeks",4]; // initialized flag to zero let flag = 0; // iterating over whole array element one by one for(let i of arr){ // checking element is of type string or not if(typeof i == 'string'){ console.log("String found"); flag = 1; } } // if flag remain same that means we didn't get the string. if(flag==0){ console.log("String not found"); }</script> |
Output:
String found
Example 2: The following code demonstrates the case where the string is absent.
Javascript
<script> // Declare the array const arr = [1,2,3,4,5]; // initialized flag to zero let flag = 0; // iterating over whole array element one by one for(let i of arr){ // checking element is of type string or not if(typeof i == 'string'){ console.log("String found"); flag = 1; } } // if flag remain same that means we didn't get the string. if(flag==0){ console.log("String not found"); }</script> |
Output:
String not found
We can identify any data type using the typeof operator. We can use it for other data types like eg. numbers, boolean, etc.
Approach 2: Using Array.some() and instanceof:
- Initialize the Array.
- Use Some method on the Array which checks the instance of each element and returns true if any string is present.
- Print Evaluated result.
Example: The following code demonstrates the case where the string is present.
Javascript
// Declare the arrayconst arr = [1, 2, "GFG", 4, 5];// initialized flag to true if string foundlet flag = arr.some(x => x instanceof String);// if flag remain same that means we didn't get the string.if (flag) { console.log("String not found");}else { console.log("String found")} |
Output:
String found
Time complexity: O(N), Where N is the length of the Array.
Auxiliary complexity: O(1), Because no extra space is used.
