Most efficient way to check if any values from an array are false based on object map

Question

I'm working with an object with keys that have one boolean value. I'm trying to figure the most efficient way to check if any values I receive from an array equal false in the object with their associated key.

For example I have an object like so:

cars = {
  bmw: true,
  lexus: true,
  audi: false,
  mercedes: false
}

Then I'll receive an array like:

allApproved(['bmw', 'audi'])  // should return false
allApproved(['bmw', 'lexus']) // should return true

If any of the values for the key false in the map, I want my function to return false. Doesn't matter how many, if any are false I want to return false. If they are all true, I will return true.

Answer 1

Use Array#every

The every() method tests whether all elements in the array pass the test implemented by the provided function.

 var cars = { bmw: true, lexus: true, audi: false, mercedes: false }; function allApproved(arr) { return arr.every(function(el) { return cars[el]; }); } console.log(allApproved(['bmw', 'audi'])); console.log(allApproved(['bmw', 'lexus'])); 

Answer 2

 cars = { bmw: true, lexus: true, audi: false, mercedes: false } function allApproved(arr) { return !arr.some(function(v) { return !cars[v]; }); } console.log(allApproved(['bmw', 'audi'])); // false console.log(allApproved(['bmw', 'lexus', 'asd'])); // true 

If there are not .some() elements in the array that don't have a corresponding true value then all are approved. (Noting that if cars doesn't have an entry for a particular brand then this code will treat that brand as false .)

Answer 3

The fastest would still be a regular old loop

function allApproved(arr) {
    for (var i=arr.length; i--;) {
        if (cars[arr[i]] === false) return false;
    }
    return true;
}