String.prototype.padStart()

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The padStart() method pads the current string with a given string (eventually repeated) so that the resulting string reaches a given length. The pad is applied from the start (left) of the current string.

Syntax

JavaScript
<var>str</var>.padStart(<var>targetLength</var> [, <var>padString</var>])

Parameters

targetLength
The length of the resulting string once the current string has been padded. If this parameter is smaller than the current string's length, the current string will be returned as it is.
padString Optional
The string to pad the current string with. If this string is too long, it will be truncated and the left-most part will be applied. The default value for this parameter is " " (U+0020).

Return value

A String of the specified length with the pad string applied from the start.

Examples

JavaScript
'abc'.padStart(10);         // "       abc"
'abc'.padStart(10, "foo");  // "foofoofabc"
'abc'.padStart(6,"123465"); // "123abc"

Specifications

This method has not yet reached the ECMAScript standard. It is currently a proposal for ECMAScript.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support ?  48 (48) ? ? ?
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? ? 48.0 (48) ? ? ?

See also

License

© 2016 Mozilla 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/padstart

Experimental JavaScript Method Reference String