# What is the first class function in JavaScript ?

**First-Class Function:** A programming language is said to have First-class functions if functions in that language are treated like other variables. So the functions can be assigned to any other variable or passed as an argument or can be returned by another function. JavaScript treat function as a first-class-citizens. This means that functions are simply a value and are just another type of object.

**Example:** Let us take an example to understand more about the first-class function.

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## Javascript

`<script>` ` ` `const Arithmetics = {` ` ` `add: (a, b) => {` ` ` `return` ``${a} + ${b} = ${a + b}`;` ` ` `},` ` ` `subtract: (a, b) => {` ` ` `return` ``${a} - ${b} = ${a - b}`` ` ` `},` ` ` `multiply: (a, b) => {` ` ` `return` ``${a} * ${b} = ${a * b}`` ` ` `},` ` ` `division: (a, b) => {` ` ` `if` `(b != 0) ` `return` ``${a} / ${b} = ${a / b}`;` ` ` `return` ``Cannot Divide by Zero!!!`;` ` ` `}` ` ` ` ` `}` ` ` ` ` `document.write(Arithmetics.add(100, 100) + ` `"<br>"` `);` ` ` `document.write(Arithmetics.subtract(100, 7) + ` `"<br>"` `);` ` ` `document.write(Arithmetics.multiply(5, 5) + ` `"<br>"` `);` ` ` `document.write(Arithmetics.division(100, 5));` `</script>` |

**Note: **In the above example, functions are stored as a variable in an object.

**Output:**

100 + 100 = 200 100 - 7 = 93 5 * 5 = 25 100 / 5 = 20

**Example 2:**

## Javascript

`<script>` ` ` `const Geek = (a, b) => {` ` ` `return` `(a + ` `" "` `+ b);` ` ` `}` ` ` ` ` `document.write(Geek(` `"Akshit"` `, ` `"Saxena"` `));` `</script>` |

**Output:**

Akshit Saxena