Script for detecting mozilla js dialect's deprecated syntaxes

Detect mozilla js dialect's deprecated syntaxes including expression closure (function (x) x * x), let expression (let (x = 10) x), and let body (let (x = 10) { x };).

Usage

Call detect_mozilla_dialect.sh with suspicious files,

./detect_mozilla_dialect.sh ./test/test.js

and the script outputs the following messages in gcc's error message style.

./test/test.js:8: expression closure is deprecated
./test/test.js:3: let expression/body is deprecated

Deprecated syntaxes

See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Deprecated_and_obsolete_features for the list of deprecated syntaxes.