Count the number of true members in an array of boolean values

Question

New to javascript and I'm having trouble counting the number of trues in an array of boolean values. I'm trying to use the reduce() function. Can someone tell me what I'm doing wrong?

   //trying to count the number of true in an array     myCount = [false,false,true,false,true].reduce(function(a,b){       return b?a++:a;     },0);     alert("myCount ="+ myCount);  // this is always 0 

Answer 1

Seems like your problem is solved already, but there are plenty of easier methods to do it.

Excellent one:

.filter(Boolean); // will keep every truthy value in an array 

const arr = [true, false, true, false, true]; const count = arr.filter(Boolean).length;  console.log(count);

Good one:

const arr = [true, false, true, false, true]; const count = arr.filter((value) => value).length;  console.log(count);

Average alternative:

let myCounter = 0;  [true, false, true, false, true].forEach(v => v ? myCounter++ : v);  console.log(myCounter);