Mustach syntax in strings and String.replace / String.replaceAll

[jyoungbt]

Hey!

I came across some weird behaviour in an event script whereby trying to use String.replace or String.replaceAll on a string containing variables with mustach syntax eg {{name}} caused the output to replace every character with the replace value passed to the method.

For example, the result of:

const s = 'Hello {{name}}, today is {{date_now}}';
console.log(s.replaceAll('{{name}}', 'Bob').replaceAll('{{date_now}}', new Date().toISOString()));

Produces:
2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010ZH2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Ze2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zl2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zl2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Z 2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Z,2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Z 2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zt2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zd2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Za2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zy2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Z 2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zi2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Zs2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Z 2026-08-28T15:38:20.010ZB2026-08-28T15:38:20.010Zo2026-08-28T15:38:20.010Zb2026-08-28T15:38:20.010Z

Changing the mustach syntax for something else fixes the issue eg. swapping the brace { for an underscore _.

We'd usually use the syntax for email templates or messages with variable content but it's not an issue to use different syntax.

[jhuckaby]

Hi there! Thank you for reporting this issue. This is caused by xyOps' mustache macro expansion system we call XYEXP.

All string-valued Plugin Parameters are processed for xyOps {{ mustache }} macros before the Plugin starts. This includes the Shell Plugin's Script Source parameter, which I suspect is what you are using here. In your example, {{name}} and {{date_now}} are evaluated against the job context and resolve to empty strings, so the code ultimately runs replaceAll('', ...). JavaScript inserts the replacement between every character when the search string is empty, which produces the output you are seeing.

For a quick workaround, you can use different template delimiters or construct the braces at runtime, for example with '\x7b\x7bname\x7d\x7d'.

If this is reusable application code that needs to contain Mustache templates naturally, creating a custom Event Plugin is the way to go. Event Plugin source code itself is not macro-processed. Note that any string parameters passed to that Plugin will still support xyOps macro expansion.

Hope this helps!

[jyoungbt]

Awesome thank you for your reply!
I replaced the braces with underscores and it's all working fine.