javascript check if array is empty or null or undefined
if(typeof array !=='undefined'&& array.length===0){// the array is defined and has no elements}if(typeof image_array !=='undefined'&& image_array.length>0){// the array is defined and has at least one element}if(array ===undefined|| array.length==0){// array empty or does not exist}if(array &&!array.length){// array is defined but has no element}if(Array.isArray(array)&& array.length){// array exists and is not empty}