Better way to check if every value in a nested array is true or false?

Question

I have a nested array like this.

var arr = [[false,false,false,false],[false,false,false,false],[false,false,false,false],[false,false,false,false]]

I want to check if every value is false. I could think of one way of doing this.

let sum = 0;
arr.forEach((row, i) => {
    row.forEach((col, j) => {
      sum = sum +arr[i][j]    
    });
});
if(sum === 0){
    console.log("all values false")
}

This works. But I'm curious if there is a better way? to check if all values are true or false?

Answer 1

You could take two nested Array#some, because if you found one true value the iteration stops. Then take the negated value.

var array = [[false, false, false, false], [false, false, false, false], [false, false, false, false], [false, false, false, false]],
    result = !array.some(a => a.some(Boolean));

console.log(result);