The trimStart()
method of String
values removes whitespace from the beginning of this string and returns a new string, without modifying the original string. trimLeft()
is an alias of this method.
The trimStart()
method of String
values removes whitespace from the beginning of this string and returns a new string, without modifying the original string. trimLeft()
is an alias of this method.
trimStart() trimLeft()
None.
A new string representing str
stripped of whitespace from its beginning (left side). Whitespace is defined as white space characters plus line terminators.
If the beginning of str
has no whitespace, a new string is still returned (essentially a copy of str
).
After trim()
was standardized, engines also implemented the non-standard method trimLeft
. However, for consistency with padStart()
, when the method got standardized, its name was chosen as trimStart
. For web compatibility reasons, trimLeft
remains as an alias to trimStart
, and they refer to the exact same function object. In some engines this means:
String.prototype.trimLeft.name === "trimStart";
The following example trims whitespace from the start of str
, but not from its end.
let str = " foo "; console.log(str.length); // 8 str = str.trimStart(); console.log(str.length); // 5 console.log(str); // 'foo '
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | Deno | Node.js | ||
trimStart |
664 | 7912 | 613.5 | 5315 | 12 | 6618 | 614 | 4714 | 12 | 9.01.0 | 66≤37 | 1.01.0 | 10.0.00.12.0 |
© 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/trimStart