Using JavaScript to Remove Null Values From an Array

We can use JavaScript to remove null values from an array by making use of a for loop with an if conditional statement. Here is a simple function we will create to remove nulls from an array.

function removeNullValues(arr){
  var new_array = [];
  for (var i=0; i<arr.length; i++){
    if( arr[i] != null ){
      new_array.push(arr[i]);
    }
  }
  return new_array;
};

In the function above, we simply create a new array, loop through all the values of the old array, and only add values that are not null to the new array.

Notice above we also make use of the push() method. This simply adds the element to the end of the array.

And here is our function in use with an example array.

var array_of_strings = ["This",null,"is","an","array",null,"with","null",null,"values","."];

function removeNullValues(arr){
  var new_array = [];
  for (var i=0; i<arr.length; i++){
    if( arr[i] != null ){
      new_array.push(arr[i]);
    }
  }
  return new_array;
};

console.log(removeNullValues(array_of_strings));

#Output:
['This', 'is', 'an', 'array', 'with', 'null', 'values', '.']

When working with arrays of strings, it can be valuable to be able to easily filter and remove unwanted values from your array.

One such situation where you may want to remove values from an array is if you have a lot of null values in your array.

We can easily remove all nulls from an array using JavaScript by simply iterating over the array and removing the null values. This is done simply with the use of a for loop and an if conditional statement.

Below again is the code for our function which will remove all instances of null values from an array in JavaScript.

function removeNullValues(arr){
  var new_array = [];
  for (var i=0; i<arr.length; i++){
    if( arr[i] != null ){
      new_array.push(arr[i]);
    }
  }
  return new_array;
};

Using JavaScript to Remove Null Values From an Array Using the Filter Method

Below shows another way we can remove null values from an array, this time by using the filter() method.

var array_of_strings = ["This",null,"is","an","array",null,"with","null",null,"values","."]

var filtered_array = array_of_strings.filter(x => x != null);

Let’s put this code in a function to make it easier to remove null values from an array.

function removeNullValues(arr){
  return arr.filter(x => x != null);
};

And now let’s give it the same example as we did to our first function above.

function removeNullValues(arr){
  return arr.filter(x => x != null);
};

var array_of_strings = ["This",null,"is","an","array",null,"with","null",null,"values","."]

console.log(removeNullValues(array_of_strings));

// Output:
['This', 'is', 'an', 'array', 'with', 'null', 'values', '.']

Hopefully this article has been useful for you to learn how to use JavaScript to remove null from an array.