File.js

const {process} = global;
const {EventTarget} = require('./Event');
const {_elementGetter, _elementSetter} = require('./utils');

class FileReader extends EventTarget {
  constructor() {
    super();

    this.result = null;
  }

  get onload() {
    return _elementGetter(this, 'load');
  }
  set onload(onload) {
    _elementSetter(this, 'load', onload);
  }

  get onerror() {
    return _elementGetter(this, 'error');
  }
  set onerror(onerror) {
    _elementSetter(this, 'error', onerror);
  }

  readAsArrayBuffer(file) {
    this.result = file.buffer.buffer.slice(file.buffer.byteOffset, file.buffer.byteOffset + file.buffer.byteLength);

    process.nextTick(() => {
      this.dispatchEvent(new Event('load', {
        target: this,
      }));
    });
  }

  readAsDataURL(file) {
    this.result = 'data:' + file.type + ';base64,' + file.buffer.toString('base64');

    process.nextTick(() => {
      this.dispatchEvent(new Event('load', {
        target: this,
      }));
    });
  }

  readAsText(file) {
    this.result = file.buffer.toString('utf8');

    process.nextTick(() => {
      this.dispatchEvent(new Event('load', {
        target: this,
      }));
    });
  }
}
module.exports.FileReader = FileReader;