DataWeave 2.2 is compatible and bundled with Mule 4.2. Standard Support for Mule 4.2 ended on May 2, 2021, and this version of Mule will reach its End of Life on May 2, 2023, when Extended Support ends.

Deployments of new applications to CloudHub that use this version of Mule are no longer allowed. Only in-place updates to applications are permitted.

MuleSoft recommends that you upgrade to the latest version of Mule 4 that is in Standard Support so that your applications run with the latest fixes and security enhancements.

leftPad(String, Number, String): String

The specified text is left-padded to the size using the padText. By default padText is " ".

Returns left-padded String or original String if no padding is necessary.

Introduced in DataWeave 2.2.0. Supported by Mule 4.2 and later.


Name Description


The input string.


The size to pad to.


The text to pad with. It defaults to one space if not specified.


This example shows how leftPad behaves with different inputs and sizes.


%dw 2.0
import * from dw::core::Strings
output application/json
   "a": leftPad(null, 3),
   "b": leftPad("", 3),
   "c": leftPad("bat", 5),
   "d": leftPad("bat", 3),
   "e": leftPad("bat", -1)


  "a": null,
  "b": "   ",
  "c": "  bat",
  "d": "bat",
  "e": "bat"

leftPad(Null, Number, String): Null

Helper function to make leftPad work with null value.

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