every.md

every

.every() works by taking a function that returns true or false. If all of the elements in the array return true, only then will the entire statement return true.

Syntax:

const result = someArray.every(function(element[, index, array]) {

})

Check out the docs.

Example

Consider the same example above, but instead of checking if any of the values are less than 21, we want to check that all of the values are equal to or greater than 21. A simple function to return if a single age is 21 or older would look like:

const twentyOneOrAbove = function (age) {
  return age >= 21;
};

// twentyOneOrAbove(20) >> false
// twentyOneOrAbove(30) >> true

We can use every to check for all the values in the array.

const twentyOneOrAbove = function (ages) {
  return ages.every(function (age) {
    return age >= 21;
  });
};

// twentyOneOrAbove(ages) >> false

Again, we can alternatively use the named function with .every().

ages.every(twentyOneOrAbove) // false