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includes()

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Yes or No? includes() gives us a simple answer!

The includes() Method

The includes() method checks if an array contains a specific item.

It returns true if found, or false if not. Simple as that!

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How includes() Works

1const pets = ["cat", "dog", "bird", "fish"];
2
3pets.includes("dog");   // true ✓
4pets.includes("cat");   // true ✓
5pets.includes("lion");  // false ✗
6
7// Great for checking before doing something
8if (pets.includes("dog")) {
9  console.log("You have a dog!");
10}
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includes() vs indexOf()

Both can check if something exists, but they return different things:

1const arr = ["a", "b", "c"];
2
3// indexOf returns a number
4arr.indexOf("b");     // 1
5
6// includes returns true/false
7arr.includes("b");    // true
8
9// includes is cleaner for just checking
10if (arr.includes("b")) {  // Easy to read!
11  // do something
12}
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Try It Yourself!

Check if different animals are in our pet array! Get a quick true or false answer.

[
cat
[0]
dog
[1]
bird
[2]
fish
[3]
]
length: 4

Practice Exercises

3 exercises to master this lesson