What is filter in JavaScript?

In JavaScript, the filter () method allows us to filter through an array - iterating over the existing values, and returning only the ones that fit certain criteria, into a new array. The filter () function runs a conditional expression against each entry in an array. If this conditional evaluates to true, the element is added to the output array.

What is array filter?

The array filter () was called upon. A value to use as this when executing callbackFn. See iterative methods. A shallow copy of a portion of the given array, filtered down to just the elements from the given array that pass the test implemented by the provided function. If no elements pass the test, an empty array will be returned.

How do I filter out a winner in JavaScript?

By using filter and accessing the index property of every item on each iteration, we can filter out each of the three winners into different variables. One of the most common uses of the third parameter (array) is to inspect the state of the array being iterated over. For example, we can check to see if there is another item left in the array.

What does the filter function do?

The filter () function goes through every object in the “students” array. filter () returns students whose class is equal to “First Grade.” The “===” operator means equality. The filter function will create a new array with these new values, accessible through the “firstGradeStudents” variable.