Space added to "from++" due to ES6 keyword

[lzilioli]

After the 1.6.0 update, jsbeautifier wants to make the following change to my code. It wants to change i++ to i ++. Is there a way to prevent this?

[bitwiseman]

Could you provide an example with more context? I have tests for i++ (https://github.com/beautify-web/js-beautify/blob/master/test/data/javascript/tests.js#L1726), so it is isn't as simple as that.

[lzilioli]

This is our .jsbeautifyrc, if that helps. We are using grunt-jsbeautifier

{
    "js": {
        "jslint_happy": true,
        "indent_with_tabs": true,
        "space_in_paren": true
    }
}

Our package.json:

$ cat package.json | grep beaut
45:    "grunt-jsbeautifier": "^0.2.8",
58:    "js-beautify": "^1.5.7",

npm install output:

[email protected] node_modules/grunt-jsbeautifier
├── [email protected]
├── [email protected] ([email protected], [email protected], [email protected], [email protected])
├── [email protected]
└── [email protected]

[email protected] node_modules/js-beautify
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected])
└── [email protected] ([email protected])

example.js

function resizeWindow( from, to ) {
    while ( from !== to ) {
        getWidthStub.returns( from );
        $( window ).trigger( 'resize' );

        if ( from < to ) {
            from++;
        } else {
            from--;
        }
    }
}

after running grunt jsbeautifier:

function resizeWindow( from, to ) {
    while ( from !== to ) {
        getWidthStub.returns( from );
        $( window ).trigger( 'resize' );

        if ( from < to ) {
            from ++;
        } else {
            from --;
        }
    }
}

Curiously, I do not see the same behavior if example.js contains

var i = 0;
i++;

[lzilioli]

After further testing, the following reduced example.js also exhibits the same issue:

if ( from < to ) {
    from++;
} else {
    from--;
}

[lzilioli]

After further digging, we have determined that this is happening likely because from is a reserved word es6, which it looks like the release aims to support. If I rename the i variable in the small test case from i to from, I see the same issue. I think we can resolve this issue on our end by renaming our variable to something else, however this may still be something you want to address in the package, as it seems from, even under the es6 spec is still a valid variable name.

[bitwiseman]

Yes, thank you for drilling in on this. Yes, from should only be treated as a keyword inside an import statement.