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Type in Find: SomethingToSearch
Type in Where (without quotes): '*.js' or '*.php' or '*.vue'

Restrict search to a file path:
Type in Find: SomethingToSearch
Type in Where (without quotes): '/some/path/to/dir/, *.js' or '/some/path/to/dir/, *.php' or '/some/path/to/dir/, *.vue'