REPL
A simple REPL(read-eval-print loop) implementation is provided in the editor
which can be open from the bottom panel GodotJS.
A dropdown list will be shown if auto-complete is available for the
input partial expression. Press Up/Down to select one, and Tab to confirm the selection.

NOTE: So far,
REPLruns on the javascript runtime theScriptLanguageusing.
And, theauto-completefeature may have side effects because the partial input is evaluated to get available candidates.