gulp build starting from jhipster-core V1.2.3 fails

Overview of the issue

Starting from jhipster-core version v1.2.3 JDL Studio gulp build fails with error:

events.js:160
      throw er; // Unhandled 'error' event
      ^
Error
    at new JS_Parse_Error (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:1526:18)
    at js_error (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:1534:11)
    at parse_error (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:1647:9)
    at Object.next_token [as input] (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:1912:9)
    at next (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:2012:25)
    at eval (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:2134:42)
    at eval (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:2073:24)
    at block_ (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:2353:20)
    at eval (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:2326:25)
    at function_ (eval at <anonymous> (c:\projects\kaido-github\jdl-studio\node_modules\uglify-js\tools\node.js:22:1), <anonymous>:2331:15)

Reproduce the error

fork and clone JDL Studio

in bower.json change from

"pegjs_parser": "https://raw.githubusercontent.com/jhipster/jhipster-core/v1.1.5/lib/dsl/pegjs_parser.js",

to (error occurs with versions 1.2.3 and 1.2.4)

"pegjs_parser": "https://raw.githubusercontent.com/jhipster/jhipster-core/v1.2.4/lib/dsl/pegjs_parser.js",

hint: can reference to local version, for example if jhipster-core and jdl-studio are cloned into same parent folder then reference is:

"pegjs_parser": "../jhipster-core/lib/dsl/pegjs_parser.js",

bower install
gulp build

Related issues

At first opened that in jhipster-core project jhipster/jhipster-core#98

Suggest a Fix

After debugging gulpfile.js with .pipe(gulpIf('*.js', uglify().on('error', function(e){console.log(e);}))) found that error occurs in line peg$c73 = function(head, tail) { return `${head}${tail.join('')}`; }, error is: Unexpected character \'`\'

Seems that changes from jhipster-core commit used more ES2015 features is causing this.

Seems that must add ES2015 support to JDL Studio gulpfile.js. Googling results that Babel is suitable for that, in package.json add "gulp-babel": "6.1.2" and in gulpfile.js add babel = require('gulp-babel')

Babel can be used with babel-preset-es2015, in package.json add "babel-preset-es2015": "6.18.0" and in gulpfile.js add .pipe(babel({presets: ['es2015']})).pipe(uglify())
Babel can be used with babili like that: .pipe(babel({presets: ['babili']}))

Additional note: starting from jhipster-core version v1.2.3 JDL internal comments //..... are not parsed with pegjs_parser.js any more. These are removed before passing JDL to pegjs_parser.js. It's possible that must adapt that change separately in JDL Studio.

jhipster / jdl-studio

gulp build starting from jhipster-core V1.2.3 fails #27