What is the best procedure to check an array is empty or not in jQuery? [duplicate]

Question

I am using like to check if array is not empty

if(array != null){
  //code 
}

I also found like that

if(Array.isArray(array)){
//code
}

and

if(array.length){
//code
}

Which one is better to use above three ?

Answer 1

I suggest to use Array.isArray and the length property of the array

if (Array.isArray(array) && array.length) {
    // code
}

because it checks if array is an array and if the length has a truthy value.

---

Comparing your attempts:

1. Truthy check

   if (array != null) { // which is basically the same as if (array) {
       //code 
   }
   

   This is true for all truthy values, like 1, 'a', {}. This result is not wanted.

2. Array check

   if (Array.isArray(array)) {
       // code
   }
   

   This checks only if array is an array, but not the length of it. Empty arrays returns true, which is not wanted.

3. Length check

   if (array.length) {
       // code
   }
   

   This works only for objects which may have a property of length, which have a truthy value.

   While this comes close to the wanted result, it might be wrong, for example with objects like

   { length: 'foo' }
   

   or with array-like objects.