JavaScript: Remove null, 0, blank, false, undefined and NaN values from an array

JavaScript Array: Exercise-24 with Solution

Remove Falsy Values

Write a JavaScript function to remove. 'null', '0', '""', 'false', 'undefined' and 'NaN' values from an array.

Sample array: [NaN, 0, 15, false, -22, '',undefined, 47, null]
Expected result: [15, -22, 47]

Visual Presentation:

Sample Solution:

JavaScript Code:

// Function to filter an array and remove falsy values
function filter_array(test_array) {
 // Initialize index to -1, arr_length to the length of the array (if not provided, default to 0),
 // resIndex to -1, and result as an empty array
 var index = -1,
 arr_length = test_array ? test_array.length : 0,
 resIndex = -1,
 result = [];
 // Iterate through the elements of the test_array using a while loop
 while (++index < arr_length) { // Get the current value from the array var value = test_array[index]; // Check if the value is truthy if (value) { // If truthy, add it to the result array and increment resIndex result[++resIndex] = value; } } // Return the filtered result array return result; } // Output the result of the filter_array function with a sample array console.log(filter_array([NaN, 0, 15, false, -22, '', undefined, 47, null])); 

Output:

[15,-22,47]

Flowchart:

ES6 Version:

// Function to filter an array and remove falsy values
const filter_array = (test_array) => {
 // Initialize index to -1, arr_length to the length of the array (if not provided, default to 0),
 // resIndex to -1, and result as an empty array
 let index = -1,
 arr_length = test_array ? test_array.length : 0,
 resIndex = -1,
 result = [];
 // Iterate through the elements of the test_array using a while loop
 while (++index < arr_length) { // Get the current value from the array let value = test_array[index]; // Check if the value is truthy if (value) { // If truthy, add it to the result array and increment resIndex result[++resIndex] = value; } } // Return the filtered result array return result; }; // Output the result of the filter_array function with a sample array console.log(filter_array([NaN, 0, 15, false, -22, '', undefined, 47, null])); 

Live Demo:

See the Pen JavaScript - Remove null, 0, blank, false, undefined and NaN values from an array - array-ex- 24 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that removes false, null, 0, "", undefined, and NaN values from an array using the filter() method.
• Write a JavaScript function that iterates over an array and retains only truthy values.
• Write a JavaScript function that creates a new array containing only truthy elements from the input array.
• Write a JavaScript function that validates the input array and returns a clean array of truthy values.

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