1if (typeof array !== 'undefined' && array.length === 0) {
2    // the array is defined and has no elements
3}
4

1if (array === undefined || array.length == 0) {
2    // array empty or does not exist
3}
4

1if (Array.isArray(array) && array.length) {
2    // array exists and is not empty
3}

1// To safely test if the array referenced by variable “array” isn’t empty:
2
3if (array && array.length) {    
4   // not empty  
5} else { 
6   // empty 
7} 
8// Note that if “array” is assigned to some other object that isn’t an array, the code will still execute the “else” part.
9
10// A possible improvement to check that the object is specifically an empty array might be this:
11
12if (array && array.constructor === Array && array.length === 0) {    
13   // strictly an empty array 
14} else { 
15   // either null, or not an array or not an empty array 
16} 

1if(array.length > 0)

1var colors=[];
2if(!colors.length){
3	// I am empty
4}else{
5	// I am not empty
6}