if array is empty in js 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 empty

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

Example 3: 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 
}