mand-mobile/lib-vw/image-reader/image-reader.js

(function (global, factory) {
  if (typeof define === "function" && define.amd) {
    define(["exports"], factory);
  } else if (typeof exports !== "undefined") {
    factory(exports);
  } else {
    var mod = {
      exports: {}
    };
    factory(mod.exports);
    global.imageReader = mod.exports;
  }
})(this, function (exports) {
  "use strict";

  Object.defineProperty(exports, "__esModule", {
    value: true
  });

  exports.default = function (global) {
    /**
     * Constructor
     * @param{*} [Array]files 图片文件
     * @param{*} [Boolean]isWebWorker 是否为webwork模式调用
     * @param{*} [Number]size 单张图片大小限制
     * @param{*} [Function]complete 非webwork模式时 回调 res { errorCode: '0', file, dataUrl }
     */
    function ImageReader(options) {
      /* istanbul ignore if */
      if (!options.files) {
        return;
      }

      this.files = options.files;
      this.index = 0;
      this.size = options.size || 0;

      if (!options.isWebWorker && options.complete) {
        this.callback = options.complete;
      }

      this.readImage(options.files[this.index]);
    }

    ImageReader.prototype.readImage = function (file) {
      var _this = this;

      // iterator
      var next = this.files && this.index < this.files.length - 1 ? function () {
        _this.index += 1;
        _this.readImage(_this.files[_this.index]);
      } : null;

      var onReadImageComplete = function onReadImageComplete() {
        var msg = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};

        /* istanbul ignore else */
        if (_this.callback) {
          _this.callback(msg);
        } else {
          postMessage(msg);
        }
        next && next();
      };

      if (!this.size || file.size <= this.size) {
        var reader = new FileReader();

        reader.onload = function (readerEvt) {
          var dataUrl = readerEvt.target.result;
          onReadImageComplete({ errorCode: 0, file: file, dataUrl: dataUrl });
        };
        reader.onerror = function () {
          /* istanbul ignore next */
          onReadImageComplete({ errorCode: 102 });
        };

        reader.readAsDataURL(file);
      } else {
        onReadImageComplete({ errorCode: 101 });
      }
    };

    var onmessageCallback = function onmessageCallback(workerEvt) {
      var imageReader = new ImageReader(workerEvt.data);
      return imageReader;
    };

    if (global) {
      return function (data) {
        return onmessageCallback({ data: data });
      };
    } else {
      /* global onmessage */
      /* eslint no-unused-vars: 0 */
      /* eslint no-global-assign: 0 */
      /* istanbul ignore next */
      onmessage = onmessageCallback;
    }
  };
});