#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)(?:\G(?!\A)|id:\s*')[^'\s]*\K\s(?=[^']*')"
Local $sString = "var user1 = {id: 'Alan Banks'};" & @CRLF & _
"var user2 = {id: 'Chris Daily'};" & @CRLF & _
"var user1 = {id: 'Alan Banks TEXT here'};" & @CRLF & _
"var user2 = {id: 'Chris Daily More text'};"
Local $sSubst = "_"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm