fd-gulp-encodingfilter/index.js

filt the assigned encoding file

'use strict';

var through = require('through');
var gutil = require('gulp-util');
var PluginError = gutil.PluginError;
var Path = require('path');
var File = gutil.File;
var Buffer = require('buffer').Buffer;
var jschardet = require('jschardet');
var FLAG = 'STYLE_BUILD_ERR ';


module.exports = function (encoding) {

  var pluginName = 'fd-gulp-encodingfilter';  
  var errorCache = [];

  if( typeof encoding !== 'string' || !encoding.trim().length ) {
    throw new PluginError(pluginName, 'encoding is empty');
  }

  function filter (file) {
    var self = this;
    
    if (file.isNull()) {
      return;
    }

    if (file.isStream()) {
      return this.emit("error", new PluginError(pluginName, 'Streaming not supported'));
    }

    var filePath = file.path;
    var filebuffer = file.contents;

    var detectObj = jschardet.detect(filebuffer);

    var fileEncoding = detectObj.encoding ? 
                        detectObj.encoding.toLowerCase() :
                        encoding;

    var filterEncoding = encoding.toLowerCase();


    if( filterEncoding !== fileEncoding ) {
       errorCache.push('file: ' + filePath +  ' encoding: ' + fileEncoding + ' confidence ' + detectObj.confidence);
    }
  }

  function endStream() {

    if (errorCache.length === 0){
      return this.emit('end');
    } 

    throw new PluginError(pluginName, FLAG + 'the file encoding should ' + encoding + ' but ' + errorCache.join('\n'))
    
  }

  return through(filter, endStream);

};