javascript how to check if array is empty

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

1if (array && !array.length) {
2    // array is defined but has no element
3}

1if (typeof image_array !== 'undefined' && image_array.length > 0) {
2    // the array is defined and has at least one element
3}

1if(array.length > 0)

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