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JavaScript - String trim() method example

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Created by:

Wiktor-Sribiew

830

In this short article, we are going to discuss how to trim strings in JavaScript.

There are 3 different ways to trim string:

both sides - most commonly used
left side
right side

Quick overlook:

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var text = '    abc    ';
​
// Both side trimming:
console.log(     'abc' === text.trim()                    ); // true
console.log(     'abc' === text.replace(/^\s*|\s*$/g, '') ); // true
​
// Left side trimming:
console.log( 'abc    ' === text.replace(/^\s*/g, '') ); // true
​
// Right side trimming:
console.log( '    abc' === text.replace(/\s*$/g, '') ); // true

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Left and right side trimming with ECMAScript 2020:

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var text = '    abc    ';
​
// left side trimming:
console.log( 'abc    ' === text.trimStart() ); // true
console.log( 'abc    ' === text.trimLeft()  ); // true
​
// right side trimming:
console.log( '    abc' === text.trimEnd()   ); // true
console.log( '    abc' === text.trimRight() ); // true

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Note: trimStart, trimLeft, trimEnd, trimRight are in draft of ECMAScript 2020, so it is better to use replace approach until the methods will be commonly supported.

More detailed and grouped substring methods description is placed below.

1. Documentation

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Syntax	`String.prototype.trim()` `String.prototype.trimStart()` or `String.prototype.trimLeft()` `String.prototype.trimEnd()` or `String.prototype.trimRight()`
Parameters	-
Result	The `trim()` method returns new string representing the string stripped of whitespace from both its beginning and end. The `trimStart()` and `trimEnd()` methods return a new string with whitespace trimmed from just one side.
Description	The `trim()` method removes whitespace from both ends of a string and returns a new string, without modifying the original one. To trim just one side of the string use `trimStart()` or `trimEnd()`.

2. Trim operation with built-in methods example

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In this section, two ways how to trim strings in javascript are represented. One of them is based on String trim method. The second one replaces white characters with regular expressions.

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var text = '    abc    ';
​
console.log( 'abc' === text.trim()                    ); // true
console.log( 'abc' === text.replace(/^\s*|\s*$/g, '') ); // true

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3. Side trimming operation with built-in methods example

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JavaScript API provides additionally left and right trimming.

3.1. Left side trimming

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xxxxxxxxxx
 
var text = '    abc    ';
​
console.log( 'abc    ' === text.replace(/^\s*/g, '') ); // true
console.log( 'abc    ' === text.trimStart()          ); // true
console.log( 'abc    ' === text.trimLeft()           ); // true

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Note: trimStart and trimLeft are in draft of ECMAScript 2020, so it is better to use replace approach until the methods will be commonly supported.

3.2. Right side trimming

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xxxxxxxxxx
 
var text = '    abc    ';
​
console.log( '    abc' === text.replace(/\s*$/g, '') ); // true
console.log( '    abc' === text.trimEnd()            ); // true
console.log( '    abc' === text.trimRight()          ); // true

Auto running

Note: trimEnd and trimRight are in draft of ECMAScript 2020, so it is better to use replace approach until the methods will be commonly supported.

Alternative titles

Show discussions ...

JavaScript - String trim() method example

1. Documentation

2. Trim operation with built-in methods example

3. Side trimming operation with built-in methods example

3.1. Left side trimming

3.2. Right side trimming

Alternative titles

JavaScript - String (documentation)

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