To check if an array is empty in JavaScript, use the length property. If the length is 0, then the array is empty.
How To Check If An Array Is Empty In JavaScript
If you want to check if an array is empty in JavaScript, there are several ways you can do it. The most common way is to use the length property of the array. This will return 0 if the array is empty.
For example:
var myArray = [];
if(myArray.length == 0) {
// the array is empty
} else {
// the array is not empty
}There is a drawback to using the length property to check if an array is empty. If the array is defined as null or undefined, the code above will throw an error trying to use length.
To workaround this, you can use the conditional chaining (?) operator to safely check if an array is empty.
For example:
var myArray = [];
if(myArray?.length == 0) {
// the array is empty or undefined
} else {
// the array is not empty
}In the above code, the conditional chaining operator (?) will short-circuit if myArray is null or undefined. If it’s not null or undefined, it will check the length property. This means you can safely use the length property to check if an array is empty without getting an error.
You can even use a typeof operator to check if a variable is not undefined before checking the length property.
For example:
var myArray = [];
if(typeof myArray != "undefined" && myArray!=null && myArray.length!=null && myArray.length == 0) {
// the array is empty or undefined
} else {
// the array is not empty
}The above code will check if myArray is not undefined, null, or has a length property that is not null. This will cover all the cases where you might get an error trying to use the length property.
Another problem with the above code is that if the variable is declared as a String, it will still return 0.
For example, the following code will return 0:
var myArray = "";
if(myArray.length == 0) {
// the array is empty or a string
} else {
// the array is not empty
}You can check if a value is a valid array by using the Array.isArray() method.
For example:
var myArray = [];
if(Array.isArray(myArray) && myArray.length>0) {
//do something
} else {
// do array
}In the above code, we first use Array.isArray() to check if myArray is an array. If it is, then we check the length property. This will work even if the array is null or undefined because Array.isArray() will return false if the value is not an array.
If the myArray variable is an array and length is greater than 0, then the array is not empty. Otherwise, the array is either empty or not an array.
Conclusion – Check If An Array Is Empty
There are several ways to check if an array is empty in JavaScript. The most common way is to use the length property. You can also use the Array.isArray() method to check if a value is an array before checking the length property.
You can also use the conditional chaining operator (?) to safely check if an array is empty without getting an error.
Finally, you can use a typeof operator to check if a variable is not undefined before checking the length property. This will cover all the cases where you might get an error trying to use the length property.