javascript check if array is empty

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

1if(typeof array != 'undefined' && array.length > 0){
2	// array has elements
3}

1if (!Array.isArray(array) || !array.length) {
2  // array does not exist, is not an array, or is empty
3  // ⇒ do not attempt to process array
4}
5

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

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

1const isNotEmpty = arr => Array.isArray(arr) && arr.length > 0;
2
3isNotEmpty([1, 2, 3]);
4// Result: true
5