In this tutorial, we will see how to check if string is empty in JavaScript.
In JavaScript, we can check it using its truthy value
or by using the ===
operator.
In JavaScript, truthy value are those values that evaluates to boolean true when encountered in a Boolean context.
JavaScript uses type conversion in Boolean contexts.
Some examples of truthy values :
if (true)
if ({})
if ([])
if (42)
if ("false")
All of the output will be true.
So now we just have to check whether there is a truthy value in the string by:
let string = '';
if (string){
console.log('Not Empty')
} else {
console.log('Empty String')
}
If condition is true, it will return "Not Empty" or else it will return "Empty String".
The strict equality operator (===) is use to check whether the string is empty or not.
Code:
let str = " ";
function isEmpty(string){
if (string.length === 0 || !string.trim()){
console.log('Empty String')
} else {
console.log('String Not Empty')
}
}
isEmpty(str)
In the above code, string.length === 0
check if the length of the string is 0 and !string.trim()
checks if the string is not made of white-space only.
So now, when string.length === 0 || !string.trim()
condition returns true, it means the string is empty and it will print our "Empty String " and if it returns false, it will print "String Not Empty" in the console.
Related Topic:
Check if a string contains a substring in Javascript
Convert String To Float in JavaScript
How to Check if Object is Empty in JavaScript