getting wrong values looping through array for a particular value in javascript

Question

I have a function that is supposed to loop through an array and count the values in the array that are true. in the example below, I am expecting a value of 4, since the values 6, 3, 30, and 7 are all truthy values while 0 is false.

function countTruthy(arr) {
    var arrayLength = arr.length;
    var truthy = 0;

    for (var i = 0; i < arrayLength; i++) {
    if(arr[i] == true) {
        truthy++
    }
  }
  
  return console.log(truthy)
}

countTruthy([6, 3, 0, 30, 7])

But the code above doesn't work and I keep getting 0 instead

Answer 1

While all non-zero numbers are truthy, it is not equal to true. Only 1 is equal to true. To double-check this, just try running 60 == true in your console and it will return false, however, if you run if (60) console.log('hi') it will print 'hi'.

tl;dr: Truthy values are not necessarily equal to true.

To fix this, just check if the value is 0 instead. Like this:

function countTruthy(arr) {
  return arr.filter(x => x != 0).length;
}

console.log(countTruthy([6, 3, 0, 30, 7]))

Also, your function can be drastically reduced with .filter(). Just filter out all the zero values then return the length of the resulting array.