Count the number of true members in an array of boolean values
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 arrayconst 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);
You're returning a++ when the value is true, which will always be zero. Post-increment happens after the value is retrieved. So on the first iteration, a is 0, and the value of a++ is also 0, even though a is incremented. Because a and b are parameters of the callback, it's a fresh a on each call.
Instead:
myCount = [true, false, true, false, true].reduce(function(a, b) { return b ? a + 1 : a;});console.log(myCount);
You should use ++a instead a++ because you have to change the value of a suddenly. a variable will be incremented after its value is returned.
myCount = [false,false,true,false,true].reduce(function(a,b){ return b? ++a:a; },0);alert("myCount ="+ myCount);