is an empty array undefined code example

Example 1: javascript check if array is not empty

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

Example 2: javascript check if array is empty

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

Example 3: js check if array is empty

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