JS-058
JavaScript diagram about includes(): a visual example of Check whether an element exists
Beginner4 min~4 min read#array#includes#search

includes()

Check whether an element exists

Goal

Learn to check whether an element exists in an array using includes().

Explanation

  • includes() checks whether an array contains a value.
  • If the value is found, it returns true.
  • If the value is absent, it returns false.
  • The method does not return the element's position.
  • includes() is very convenient for quick checks.

Analogy

You look in the refrigerator to check whether there is any milk. There are only two possible answers: yes or no.

Code

const fruits = [
  "Apple",
  "Banana",
  "Orange"
];

console.log(fruits.includes("Banana"));
console.log(fruits.includes("Mango"));

Result: true false

Common mistake

Beginners sometimes expect to get the element's position. Use indexOf() for that.

Remember

  • ✦ includes() returns true or false.
  • ✦ It is used to check whether a value exists.
  • ✦ It does not return the element's index.

Quick Quiz

What does ["Apple", "Banana"].includes("Banana") return?

Resources