Write a function that filters out all the falsy values from a given array.

This content originally appeared on DEV Community and was authored by Ajay Marathe

 const removeFalsyValues = (arr) => {
    let truthy = []

    for(let i = 0; i < arr.length; i++){
      if(arr[i]) {
        truthy.push(arr[i])
      }
    }

    return truthy;

  }

  console.log('removeFalsyValues:', removeFalsyValues([0, 1, false, 2, "", 3, undefined, NaN, null]))

Falsy values in JavaScript are values that are considered false when evaluated in a Boolean context. These include0, false, "" (an empty string), undefined, NaN, and null.

Here’s how the function works:

• Initialize an empty array: The function starts by creating an empty array called truthy. This will be used to store the values from the original array that are not falsy.
• Loop through the array: The function uses a for loop to go through each element in the input array arr.
• Check if the element is truthy: Inside the loop, there’s an if statement that checks if the current element (arr[i]) is truthy. If the element is truthy (meaning it’s not one of the falsy values), it gets added to the truthy array.
• Return the truthy array: After the loop has gone through all the elements, the function returns the truthy array, which now contains only the truthy values.
• The input array is [0, 1, false, 2, "", 3, undefined, NaN, null].
• The function will loop through each element and remove the falsy ones (0, false, "", undefined, NaN, null).
• The remaining truthy values (1, 2, 3) are returned in a new array:[1, 2, 3].

So, the output of this code will be:removeFalsyValue [1, 2, 3].

This content originally appeared on DEV Community and was authored by Ajay Marathe