report of unreachable code

[GarryFlemings]

Windows 10 on a Toshiba laptop, AMD A6
Node v6.2.0
bluebird v3.4.6
webpack v1.13.2
uglify-js v2.6.4

unknown whether this affects any other version of bluebird

issue: report of unreachable code, line 5421

background: I used webpack to create a deployment bundle. It called UglifyJs, which reported the above as an Error. In my copy of the bluebird code, I see, starting with line 5414:

function toFastProperties(obj) {
/jshint -W027,-W055,-W031/
function FakeConstructor() {}
FakeConstructor.prototype = obj;
var l = 8;
while (l--) new FakeConstructor();
return obj;
eval(obj);
}

I reversed the last two code lines, making:

function toFastProperties(obj) {
/jshint -W027,-W055,-W031/
function FakeConstructor() {}
FakeConstructor.prototype = obj;
var l = 8;
while (l--) new FakeConstructor();
eval(obj);
return obj;
}

Right or wrong for you, it made the error go away for me.

If I can provide more info that'll help, please let me know.

[bergus]

The code is unreachable on purpose. Have a look at https://stackoverflow.com/q/24987896/1048572?how-does-bluebirds-util-tofastproperties-function-make-an-objects-properties
Are you sure you have to run Uglify on Bluebird, it comes with an already minified version?

[ORESoftware]

JavaScript warning: https://cdnjs.cloudflare.com/ajax/libs/bluebird/3.5.0/bluebird.js, line 5438: unreachable code after return statement
JavaScript warning: https://cdnjs.cloudflare.com/ajax/libs/bluebird/3.5.0/bluebird.js, line 5438: unreachable code after return statement