How to use MEL in dataweave to replace characters in a string - mule

Question

I am using Anypoint Studio 6.1 and Mule 3.8.1 and have this MEL expression that replaces any text \n with a new line/carriage return.
payload.replace('\\n', System.getProperty('line.separator'))
I would like to move this functionality into Dataweave but cannot get the MEL expression to work or find a way to do this in Dataweave.
How can I reuse the MEL expression in Dataweave?
Thanks

Answer 1

You should investigate Global Functions
Like:
<configuration doc:name="Global MEL-Functions">
<expression-language>
<global-functions file="mel/extraFunctions.mvel">
</global-functions>
</expression-language>
</configuration>
And create your the global function in a resoruce file for reuse
def UUID() {
return java.util.UUID.randomUUID().toString();
}
def decode(value) {
return java.util.Base64.getDecoder().decode(value);
}
def encode(value) {
return java.util.Base64.getEncoder().encodeToString(value.getBytes());
}
def stringToAscii(value) {
StringBuilder sb = new StringBuilder();
for (char c : value.toCharArray())sb.append((int)c);
return new BigInteger(sb.toString());
}
And reference your global functions in your dataweave
payload map
{
target: stringToAscii($) as :string
}

Answer 2

DW is its own mini-language within Mule aside from MEL is how it was described to me and uses a different syntax to do what you are trying. I have not done new lines specifically as my DW expressions use line separators as record separators, but the same general tactic should work. Here is an example of changing commas to spaces within a dw payload mapping:
AcctID: $.ACCOUNT_ID replace "," with " ",