Default parameter values are not recognized #1375

mgol · 2015-05-14T12:50:57Z

With esnext enabled, the following is still rejected by JSCS:

function f({param = false}={}) {}

The message is:

Unexpected token = at app/modules/services/get-raw-text.js :
    1 | function f({param = false}={}) {}
---------------------------^

The text was updated successfully, but these errors were encountered:

hzoo · 2015-05-14T12:54:05Z

If this is because of Unexpected token then it probably means you need to use a different parser. Did you try esprima-fb or the latest esprima@2.2.0?

difosfor · 2015-05-14T12:56:12Z

And how do you go about using another parser? Is there an option for that?

Shouldn't this just work when you enable esnext?

hzoo · 2015-05-14T12:56:36Z

Yeah it's the esprima option in cli or config - should be in the docs: http://jscs.info/overview.html#cli.

jscs ./ --esprima=esprima-fb if installed globally

// .jscsrc
// npm install esprima-fb
{
  "esprima": "./node_modules/esprima-fb"
}

Also I think it doesn't work because esnext turns on jscs' custom esprima branch (https://github.com/jscs-dev/esprima-harmony) which hasn't been updated to the latest yet. This is assuming the latest esprima does support this (and copying into http://esprima.org/demo/parse.html it does).

difosfor · 2015-05-14T13:04:13Z

Will this be included in jscs anytime soon? We use jscs in several ways so I'd really rather not have to introduce another dependency besides it. Or are you waiting for another parser to provide better ES6 support?

Also, if I'm not interested in JSX and other React things, but just in ES6+ will using esprima-fb not get in my way?

difosfor · 2015-05-14T13:13:31Z

Ah, just read in changelog (http://jscs.info/changelog.html) for v1.13.0:

"We eagerly wait for the Esprima 2.3 release, since soon after, esnext option will be set to true by default."

Hopefully then this will be supported out of the box.

Thanks for your pointers to help us out in the meanwhile hzoo!

hzoo · 2015-05-14T13:21:47Z

If you aren't using JSX/etc, you can using esprima@2.2.0 as a dependency or wait for our release. I'm also working on https://github.com/jscs-dev/babel-jscs which will use babel as the parser for ES6+, which I'm thinking can just be released when the next jscs is released?

difosfor · 2015-05-14T13:27:13Z

Interesting, we're using Babel for the ES Next transpiling, so I guess it would make sense to use the same parser for jscs. Though theoretically at least in the end it should all be standard and not really matter.

hzoo · 2015-05-14T13:29:09Z

Well the project has to convert acorn -> esprima so there will be a lot more bugs/issues initially, so it depends on if you are using newer features that aren't covered in esprima.

mrjoelkemp · 2015-05-15T02:27:36Z

Closing because it seems like using another parser is a workaround in the mean time.

mgol · 2015-05-22T10:20:06Z

When is it planned to switch to a newer Esprima by default?

hzoo · 2015-05-22T10:40:22Z

Maybe when esprima 2.3 is released - not sure yet?

mgol · 2015-06-02T13:08:06Z

I tried both esprima@2.2.0 & esprima-fb@15001.1.0-dev-harmony-fb and both fail on this code.

hzoo · 2015-06-02T13:20:49Z

@mzgol - If you need it now you can use https://github.com/hzoo/babel-jscs. (Not on npm yet and will be when I move to https://github.com/jscs-dev/babel-jscs

{
  "node-jscs": "jscs-dev/node-jscs#master",
  "babel-jscs": "hzoo/babel-jscs#master"
}

mgol · 2015-06-02T13:25:25Z

@hzoo thanks for the info

mgol · 2015-06-12T13:23:09Z

@hzoo BTW, the Esprima playground uses Esprima 2.2.0 and it handles such things just fine:
http://esprima.org/demo/parse.html?code=%2F%2F%20Life%2C%20Universe%2C%20and%20Everything%0Avar%20answer%20%3D%20%5B%0A%20%20%20%20...a%2C%0A%20%20%20%20'creatorDetails.creatorCore'%2C%0A%20%20%20%20'titleDetails.titleCore'%2C%0A%20%20%20%20...leftColumn%2C%0A%20%20%20%20...rightColumn%2C%0A%5D%3B%0A%0Avar%20b%20%3D%20%7B%0A%20%20%20%20f()%20%7B%7D%0A%7D%3B

and yet JSCS with Esprima 2.2.0 installed and:

{
  "esprima": "esprima",
  "esnext": true
}

recongizes neither spread nor shorthand method definitions. Perhaps JSCS invokes Esprima with options that don't support ES6?

hzoo · 2015-06-12T14:21:07Z

@mzgol It should work - it's working fine for me?
Oh (I am still confused about this), but I'm using "esprima": "./node_modules/esprima",. Also you don't need "esnext": true if you use the esprima option I think.

Also "esprima": "babel-jscs", works now if you npm install.

mgol · 2015-06-15T20:56:37Z

@hzoo I still can't get it to work with regular JSCS 1.13.1 & Esprima 2.2.0 with "esprima": "./node_modules/esprima":

$ ./node_modules/grunt-jscs/node_modules/jscs/bin/jscs .
Error: Unknown node type RestElement.
    at Controller.traverse (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/node_modules/estraverse/estraverse.js:517:31)
    at Object.traverse (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/node_modules/estraverse/estraverse.js:709:27)
    at Object.iterate (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/lib/tree-iterator.js:9:20)
    at Object.JsFile.iterate (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/lib/js-file.js:359:29)
    at Object.JsFile._buildNodeIndex (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/lib/js-file.js:752:14)
    at Object.JsFile (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/lib/js-file.js:39:28)
    at StringChecker._createJsFileInstance (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/lib/string-checker.js:202:16)
    at StringChecker.checkString (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/lib/string-checker.js:104:25)
    at null.<anonymous> (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/jscs/lib/checker.js:43:21)
    at Array.<anonymous> (/Users/mgol/Documents/projects/bn/cbn/repo/polona-gui/node_modules/grunt-jscs/node_modules/vow/lib/vow.js:711:39)

This is happening both with "esnext": true and without it.

hzoo · 2015-06-15T21:53:03Z

Ok can reproduce @mzgol it's because it doesn't know about the new node types in the newer esprima (estraverse needs to be updated). So I guess you can't really use the latest esprima at the moment unless we updated that.

In the meantime you can try https://github.com/jscs-dev/babel-jscs and see if that works for you (seems to work for me).

Kind of related to jscs-dev/babel-jscs#3 @mrjoelkemp - if we patch the new types in for estraverse from babel or just update estraverse version.

mgol · 2015-06-16T11:29:23Z

@hzoo I'd love to try babel-jscs but I use grunt-jscs and it doesn't seem to be possible to swap the JSCS package used.

mrjoelkemp · 2015-06-16T11:50:14Z

You should be able to just set the esprima option in your jscs grunt target
and it will be passed through to jscs.

@hzoo worth adding those Grunt jscs instructions to the readme of
babel-jscs.
On Jun 16, 2015 7:29 AM, "Michał Gołębiowski" notifications@github.com
wrote:

@hzoo https://github.com/hzoo I'd love to try babel-jscs but I use
grunt-jscs https://github.com/jscs-dev/grunt-jscs and it doesn't seem
to be possible to swap the JSCS package used.

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Reply to this email directly or view it on GitHub
#1375 (comment)
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hzoo · 2015-06-16T11:56:06Z

Yeah @mzgol babel-jscs is a esprima parser option (just like esprima)
In the readme it does say

// .jscsrc
{
  "esprima": "esprima", // instead of this
  "esprima": "babel-jscs", // global
  "esprima": "./node_modules/babel-jscs", // local
}

It's the same for grunt right? I see

// Gruntfile.js
jscs: {
    src: "path/to/files/*.js",
    options: {
        config: ".jscsrc"
   }
}

mgol · 2015-06-16T16:31:33Z

@hzoo Ah, thanks, I assumed it's JSCS replacement, not Esprima one as technically speaking Esprima 2.2.0 supports the constructs I care about.

I found 2 blocker issues after the switch: one is an already-reported non-working validateQuoteMarks, another one is jscs-dev/babel-jscs#4.

mrjoelkemp closed this as completed May 15, 2015

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Default parameter values are not recognized #1375

Default parameter values are not recognized #1375

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mgol commented Jun 16, 2015

Default parameter values are not recognized #1375

Default parameter values are not recognized #1375

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