codenothing/Nlint

var JSCS = require( 'jscs/lib/checker.js' ),
    rnewline = /\r\n|\r|\n/;

module.exports = {

    name: 'JSCS',
    match: 'js',

    render: function( path, contents, settings, callback ) {
        var errors = [],
            checker = new JSCS(),
            results = [],
            lines = contents.trim().split( rnewline ),
            lintError;

        try {
            checker.registerDefaultRules();
            checker.configure( settings );
            results = checker.checkString( contents ).getErrorList();
        }
        catch ( e ) {
            if ( typeof e == 'string' ) {
                lintError = new Error( e );
            }
            else if ( ! ( e instanceof Error ) ) {
                lintError = new Error( "Unknown JSCS Error - " + e );
            }
            else {
                lintError = e;
            }

            errors.push({
                path: path,
                message: lintError.stack,
                line: lintError.lineNumber || 0,
                character: 0,
            });

            return callback( null, errors, null );
        }

        if ( results && results.length ) {
            results.forEach(function( e ) {
                var line = e.line - 1;

                if ( line === 0 ) {
                    line++;
                }
                else if ( line === lines.length - 1 ) {
                    line--;
                }

                errors.push({
                    path: path,
                    message: e.message,
                    line: e.line,
                    character: e.column,
                    evidence: [
                        line + "| " + lines[ line - 1 ],
                        ( line + 1 ) + "| " + lines[ line ],
                        ( line + 2 ) + "| " + lines[ line + 1 ],
                    ].join( "\n" ),
                });
            });
        }

        // callback( Actual error, lint errors, lint warnings )
        callback( null, errors, null );
    }
};