# JavaScript Math trunc()

The `trunc()` method truncates (shortens) a number and returns its integer portion.

### Example

``````let number = Math.trunc("420.56");
console.log(number);

// Output: 420``````

## trunc() Syntax

The syntax of the `Math.trunc()` method is:

``Math.trunc(number)``

Here, `trunc()` is a static method. Hence, we are accessing the method using the class name, `Math`.

## trunc() Parameter

The `trunc()` method takes a single parameter:

• `number` - value that needs to be truncated (shortened to integer)

## trunc() Return Value

The `trunc()` method returns:

• integer part of a `number`
• NaN (Not a Number) for a non-numeric argument

## Example 1: JavaScript Math.trunc()

``````// trunc() with a negative number
let number1 = Math.trunc(-50.456);
console.log(number1);

// trunc() with a positive number
let number2 = Math.trunc(18.645);
console.log(number2);

// Output:
// -50
// 18``````

Here, the `Math.trunc()` returns

• -50 - for the negative number `-50.45627`
• 18 - for the positive number `18.645`

Note: The `trunc()` method does not round off a number, it just removes the digits after the decimal point and returns the integer portion.

## Example 2: JavaScript Math.trunc() with Numeric String

``````// trunc() with a numeric string
let number2 = Math.trunc("15.645");
console.log(number2);

//Output:15``````

In the above example, `Math.trunc("15.645")` converts the numeric string to a number and truncates it.

## Example 3: JavaScript Math.trunc() with Non-Numeric Argument

``````let string = "Luke";
// trunc() with string argument
let value = Math.trunc(string);
console.log(value);

// Output: NaN``````

In the above example, we have used the `trunc()` method with a string argument `"Luke"`. That's why we get NaN as output.