使用ES6+工厂模式模拟jquery代码

class jQuery {
  constructor(selector) {
    let splitSelector = selector.match(/([$#])(.*)/);
    if (splitSelector) {
      if (Object.is(splitSelector[1], '$')) {
        this.dom = document.querySelectorAll(splitSelector[2]);
      } else if (Object.is(splitSelector[1], '#')) {
        this.dom = document.getElementById(splitSelector[2]);
      } else {
        this.dom = document.querySelectorAll(selector);
      }
    } else {
      this.dom = document.querySelectorAll(selector);
    }
  }

  _isObject(obj) {
    const _toString = Object.prototype.toString;
    return Object.is(_toString.call(obj), '[object Object]');
  }

  addClass(className) {
    if (className) {
      if (this.dom.className) {
        let classList = this.dom.className.split(' ');
        let classNameList = className.split(' ');
        let concatClassList = classList.concat(classNameList);
        concatClassList = [...new Set(concatClassList)];
        this.dom.className = concatClassList.join(' ');
      } else {
        this.dom.className = `${className}`;
      }
    } else {
      throw new Error('必须传递参数');
    }
    return this;
  }

  removeClass(className) {
    if (className) {
      let classList = this.dom.className.split(' ');
      classList.splice(classList.findIndex(item => Object.is(item, className)), 1);
      this.dom.className = classList.join(' ');
    } else {
      throw new Error('必须传递参数');
    }
    return this;
  }

  html(data) {
    this.dom.innerHTML = data;
    return this;
  }

  css(params) {
    if (params) {
      if (this._isObject(params)) {
        for (let key in params) {
          this.dom.style[key] += params[key];
        }
      } else {
        if (arguments.length != 2) {
          throw new Error();
        } else {
          this.dom.style[arguments[0]] = arguments[1];
        }
      }
    } else {
      throw new Error('必须传递参数');
    }
    return this;
  }
}

window.$ = function (selector) {
  return new jQuery(selector);
};

// 测试代码
$('#div1').html('你好').addClass('cc dd bb').removeClass('bb').css({'color': '#f00', 'font-size': '20px'});