How to use the typeof operator In Javascript
In JavaScript, the typeof operator returns the data type of its operand in the form of a string. The operand can be any object, function, or variable. If the value is undefined, then it doesn’t exist.
Syntax:
typeof (operand);
Example: In this example, we will see the use of typeof operator for checking the value.
let arr = [1, 2, 3, 4, 5];
let value = 3;
if (typeof arr[value] !== "undefined") {
console.log(`Value ${value} exists
at index ${value - 1}`);
} else {
console.log(`Value ${value} doesn't
exist at index ${value - 1}`);
}
Output
Value 3 exists
at index 2
How to Check a Value Exist at Certain Array Index in JavaScript ?
Determining if a value exists at a specific index in an array is a common task in JavaScript. This article explores various methods to achieve this, providing clear examples and explanations to enhance your coding efficiency.
Below are the different ways to check if a value exists at a specific index in an array:
Table of Content
- Using the typeof operator
- Using the in operator
- Using the hasOwnProperty() method
- Using lodash _.includes() method
- Using the indexOf method