JavaScript Array every() Method


The JavaScript array every() method checks whether all the given elements in an array are satisfying the provided condition. It returns true when each given array element satisfying the condition otherwise false.

JavaScript array every method tests whether all the elements in an array passes the test implemented by the provided function.

The every() method executes the function once for each element present in the array:

  • If it finds an array element where the function returns a false value, every() returns false (and does not check the remaining values)
  • If no false occur, every() returns true

Syntax

array.every(function(currentValue, index, arr), thisValue)

Example

Check if all the answer values in the array are the same:

<script>
var survey = [
  { name: "Steve", answer: "Yes"},
  { name: "Jessica", answer: "Yes"},
  { name: "Peter", answer: "Yes"},
  { name: "Elaine", answer: "No"}
];

function isSameAnswer(el, index, arr) {
  if (index === 0){
    return true;
  } else {
    return (el.answer === arr[index - 1].answer);
  }
}

function myFunction() {
  document.getElementById("demo").innerHTML = survey.every(isSameAnswer);
}
</script>

Example -