prependIfMissing

prependIfMissing(text: String, prefix: String): String

Prepends the prefix to the beginning of the string if the text does not already start with that prefix.

Introduced in DataWeave version 2.2.0.

Parameters

Name Description

Name	Description
`text`	The input string.
`prefix`	The text to use as prefix.

text

The input string.

prefix

The text to use as prefix.

Example

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

Source

%dw 2.0
import prependIfMissing from dw::core::Strings
output application/json
---
{
  "a": prependIfMissing(null, ""),
  "b": prependIfMissing("abc", ""),
  "c": prependIfMissing("", "xyz"),
  "d": prependIfMissing("abc", "xyz"),
  "e": prependIfMissing("xyzabc", "xyz")
}DataWeave

Output

{
  "a": null,
  "b": "abc",
  "c": "xyz",
  "d": "xyzabc",
  "e": "xyzabc"
}JSON

prependIfMissing(text: Null, prefix: String): Null

Helper function that enables prependIfMissing to work with a null value.

Introduced in DataWeave version 2.2.0.