Minify: Does not properly handle object destructuring

[hatched]

Using:

"babel-cli": "^6.18.0",
"babel-plugin-transform-react-jsx": "^6.8.0",
"babel-preset-babili": "0.0.9",
Node 6.2.0

      const min = babel.transform(data, {
        presets: ['babel-preset-babili'],
        plugins: ['transform-react-jsx'],
        compact: true,
        comments: false
      });

The following code:

    if (parts.includes(PATH_DELIMETERS.get('user'))) {
      ({state, parts, error} = this._parseUser(parts, state));
      if (error !== null) {
        error = `cannot parse the User path: ${error}`;
        return {error, state};
      }
    }

gets converted to the following. You'll notice that both parts and error are j.

        if (j.includes(PATH_DELIMETERS.get('user')) && (( { state : h , parts : j , error : j } = this._parseUser(j, h)),
        null !== g))
            return g = `cannot parse the User path: ${g}`,
            {
                error: g,
                state: h
            };

Removing the object destructuring corrects the problem.

    if (parts.includes(PATH_DELIMETERS.get('user'))) {
      let parsed = this._parseUser(parts, state);
      state = parsed.state;
      parts = parsed.parts;
      error = parsed.error;
      if (error !== null) {
        error = `cannot parse the User path: ${error}`;
        return {error, state};
      }
    }

        if (j.includes(PATH_DELIMETERS.get('user'))) {
            let n = this._parseUser(j, h);
            if (h = n.state,
            j = n.parts,
            g = n.error,
            null !== g)
                return g = `cannot parse the User path: ${g}`,
                {
                    error: g,
                    state: h
                }
        }

This has also happened in other places in the script where there was destructuring.

[boopathi]

Interesting. A mangler bug. I'll take a look.

Snippet reproducing the error -

function a() {
    let foo, bar, baz;
    ({foo, bar, baz} = {});
    return {foo, bar, baz};
}

output:

function a(){
  let b,c,d;
  return({ foo: d, bar: c, baz: d } = {}), { foo: b, bar: c, baz: d };
}