Why is `f(?=\=)` invailid regex in VSCode?

user_7934600 0
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In VSCode if I use f(?=\=) in the regex find and replace I get an error that says:

Invalid regular expression: /f(?=\=)/: Invalid escape

however, if I do f(?==) it works fine. I don't see any issue with the first regex, its just a specifying the literal = sign as a positive lookahead. Why can you not escape an = sign?

visual-studio-code regex-lookarounds replace regex
1 Answers

In your regex, (?= starts a positive lookahead, but your second = is the part being matched, not part of that specific syntax. So the slash is interpreted as an escape, and an escaped = sign is invalid.

user_3568870
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