fd-gulp-convert-encoding/index.js

convert file to assigned charset

'use strict';

var through = require('through2');
var gutil = require('gulp-util');
var PluginError = gutil.PluginError;
var jschardet = require('jschardet');
var iconv = require('iconv-lite');
var FLAG = 'STYLE_BUILD_ERR ';


module.exports = function (encoding) {

  var pluginName = 'fd-gulp-convert-encoding';  

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

  function convert (file, env, callback) {
    
    if (file.isNull()) {
      return callback(null, file);
    }

    if (file.isStream()) {
      return callback(new PluginError(pluginName, 'Streaming not supported'));
    }

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

    var fileEncoding = jschardet.detect(filebuffer).encoding;
    var convertEncoding = encoding.trim();

    if( !fileEncoding ) {
      return callback(null, file);
    }

    if( !iconv.encodingExists(convertEncoding) ) {
      gutil.log(gutil.colors.yellow('[WARN]'), 'you want convert file:', filePath, 'encoding is', gutil.colors.red(fileEncoding), 'to', gutil.colors.yellow(convertEncoding) ,'but iconv-lite not support it!');
      return callback(null, file);
    }

    var fileStr = iconv.decode(filebuffer, fileEncoding);
    var decodeBuffer = iconv.encode(fileStr, convertEncoding);

    file.contents = decodeBuffer;

    return callback(null, file);
  }

  return through.obj(convert);
};