if array empty javascript code example

Example 1: javascript check if array is empty

if (typeof array !== 'undefined' && array.length === 0) {
    // the array is defined and has no elements
}

Example 2: javascript check if array is not empty

if (array === undefined || array.length == 0) {
    // array empty or does not exist
}

Example 3: javascript check if array is empty

if (array && !array.length) {
    // array is defined but has no element
}

Example 4: javascript not empty array not string

if (Array.isArray(array) && array.length) {
    // array exists and is not empty
}

Example 5: check array empty or not in javascript

// To safely test if the array referenced by variable “array” isn’t empty:

if (array && array.length) {    
   // not empty  
} else { 
   // empty 
} 
// Note that if “array” is assigned to some other object that isn’t an array, the code will still execute the “else” part.

// A possible improvement to check that the object is specifically an empty array might be this:

if (array && array.constructor === Array && array.length === 0) {    
   // strictly an empty array 
} else { 
   // either null, or not an array or not an empty array 
}

Example 6: javascript empty array

arr = [];   // set array=[]

//function
const empty = arr => arr.length = 0;
//example
var arr= [1,2,3,4,5];
empty(arr) // arr=[]