const vm = new Vue({
  data: {
      name: '我是pino',
  },
  methods: {
      print(){
          console.log(this.name);
      }
  },
});
console.log(vm.name); // 我是pino
vm.print(); // 我是pino

function Super(options){}

const p = new Super({
    data: {
        name: 'pino'
    },
    methods: {
        print(){
            console.log(this.name);
        }
    }
});

console.log(p.name); // undefined
p.print(); // p.print is not a function

function Vue (options) {
  if (process.env.NODE_ENV !== 'production' &&
    !(this instanceof Vue)
  ) {
    warn('Vue is a constructor and should be called with the `new` keyword')
  }
  this._init(options)
}
// 初始化操作是在這個函數(shù)完成的
initMixin(Vue)
stateMixin(Vue)
eventsMixin(Vue)
lifecycleMixin(Vue)
renderMixin(Vue)
export default Vue

export function initMixin (Vue: Class<Component>) {
  Vue.prototype._init = function (options?: Object) {
    const vm: Component = this
    // a uid
    vm._uid = uid++
    let startTag, endTag
    /* istanbul ignore if */
    if (process.env.NODE_ENV !== 'production' && config.performance && mark) {
      startTag = `vue-perf-start:${vm._uid}`
      endTag = `vue-perf-end:${vm._uid}`
      mark(startTag)
    }
    // a flag to avoid this being observed
    vm._isVue = true
    // merge options
    if (options && options._isComponent) {
      // optimize internal component instantiation
      // since dynamic options merging is pretty slow, and none of the
      // internal component options needs special treatment.
      initInternalComponent(vm, options)
    } else {
      vm.$options = mergeOptions(
        resolveConstructorOptions(vm.constructor),
        options || {},
        vm
      )
    }
    /* istanbul ignore else */
    if (process.env.NODE_ENV !== 'production') {
      initProxy(vm)
    } else {
      vm._renderProxy = vm
    }
    // expose real self
    vm._self = vm
    initLifecycle(vm)
    initEvents(vm)
    initRender(vm)
    callHook(vm, 'beforeCreate')
    initInjections(vm) // resolve injections before data/props
    // 初始化data/methods...
    initState(vm)
    initProvide(vm) // resolve provide after data/props
    callHook(vm, 'created')
  }
}

function initState (vm) {
    vm._watchers = [];
    var opts = vm.$options;
    // 判斷props屬性是否存在，初始化props
    if (opts.props) { initProps(vm, opts.props); }
    // 有傳入 methods，初始化方法methods
    if (opts.methods) { initMethods(vm, opts.methods); }
    // 有傳入 data，初始化 data
    if (opts.data) {
      initData(vm);
    } else {
      observe(vm._data = {}, true /* asRootData */);
    }
    // 初始化computed
    if (opts.computed) { initComputed(vm, opts.computed); }
    // 初始化watch
    if (opts.watch && opts.watch !== nativeWatch) {
      initWatch(vm, opts.watch);
    }
}

function initMethods (vm, methods) {
    var props = vm.$options.props;
    for (var key in methods) {
      {
          // 判斷是否為函數(shù)
        if (typeof methods[key] !== 'function') {
          warn(
            "Method \"" + key + "\" has type \"" + (typeof methods[key]) + "\" in the component definition. " +
            "Did you reference the function correctly?",
            vm
          );
        }
        
        // 判斷props存在且props中是否有同名屬性
        if (props && hasOwn(props, key)) {
          warn(
            ("Method \"" + key + "\" has already been defined as a prop."),
            vm
          );
        }
        // 判斷實例中是否有同名屬性，而且是方法名是保留的 _ $ （在JS中一般指內(nèi)部變量標識）開頭
        if ((key in vm) && isReserved(key)) {
          warn(
            "Method \"" + key + "\" conflicts with an existing Vue instance method. " +
            "Avoid defining component methods that start with _ or $."
          );
        }
      }
      // 將methods中的每一項的this指向綁定至實例
      // bind的作用就是用于綁定指向，作用同js原生的bind
      vm[key] = typeof methods[key] !== 'function' ? noop : bind(methods[key], vm);
    }
}

function polyfillBind (fn, ctx) {
    function boundFn (a) {
      var l = arguments.length;
      // 判斷參數(shù)的個數(shù)來分別使用call/apply進行調(diào)用
      return l
        ? l > 1
          ? fn.apply(ctx, arguments)
          : fn.call(ctx, a)
        : fn.call(ctx)
    }
    boundFn._length = fn.length;
    return boundFn
}
function nativeBind (fn, ctx) {
  return fn.bind(ctx)
}
// 判斷是否支持原生的bind方法
var bind = Function.prototype.bind
  ? nativeBind
  : polyfillBind;

// 只判斷是否為本身擁有，不包含原型鏈查找
var hasOwnProperty = Object.prototype.hasOwnProperty; 
function hasOwn (obj, key) { 
    return hasOwnProperty.call(obj, key) 
}
hasOwn({}, 'toString') // false
hasOwn({ name: 'pino' }, 'name') // true

function isReserved (str) {
  var c = (str + '').charCodeAt(0);
  return c === 0x24 || c === 0x5F
}
isReserved('_data'); // true
isReserved('data'); // false

function initData (vm) {
    var data = vm.$options.data;
    // 判斷data是否為函數(shù)，如果是函數(shù)，在getData中執(zhí)行函數(shù)
    data = vm._data = typeof data === 'function'
      ? getData(data, vm)
      : data || {};
    // 判斷是否為對象
    if (!isPlainObject(data)) {
      data = {};
      warn(
        'data functions should return an object:\n' +
        'https://vuejs.org/v2/guide/components.html#data-Must-Be-a-Function',
        vm
      );
    }
    // proxy data on instance
    // 取值 props/methods/data的值
    var keys = Object.keys(data);
    var props = vm.$options.props;
    var methods = vm.$options.methods;
    var i = keys.length;
    // 判斷是否為props/methods存在的屬性
    while (i--) {
      var key = keys[i];
      {
        if (methods && hasOwn(methods, key)) {
          warn(
            ("Method \"" + key + "\" has already been defined as a data property."),
            vm
          );
        }
      }
      if (props && hasOwn(props, key)) {
        warn(
          "The data property \"" + key + "\" is already declared as a prop. " +
          "Use prop default value instead.",
          vm
        );
      } else if (!isReserved(key)) {
        // 代理攔截
        proxy(vm, "_data", key);
      }
    }
    // observe data
    // 監(jiān)聽數(shù)據(jù)
    observe(data, true /* asRootData */);
}

function getData (data, vm) {
    // #7573 disable dep collection when invoking data getters
    pushTarget();
    try {
      // 將this綁定至實例
      return data.call(vm, vm)
    } catch (e) {
      handleError(e, vm, "data()");
      return {}
    } finally {
      popTarget();
    }
}

// 一個純凈函數(shù)
function noop (a, b, c) {}
// 代理對象
var sharedPropertyDefinition = {
    enumerable: true,
    configurable: true,
    get: noop,
    set: noop
};
function proxy (target, sourceKey, key) {
    // get攔截
    sharedPropertyDefinition.get = function proxyGetter () {
      return this[sourceKey][key]
    };
    // set攔截
    sharedPropertyDefinition.set = function proxySetter (val) {
      this[sourceKey][key] = val;
    };
    // 使用Object.defineProperty對對象進行攔截
    Object.defineProperty(target, key, sharedPropertyDefinition);
}

  function Person(options) {
      let vm = this
      vm.$options = options
      if(options.data) {
        initData(vm)
      } 
      if(options.methods) {
        initMethods(vm, options.methods)
      }
    }
    function initData(vm) {
      let data = vm._data = vm.$options.data
      let keys = Object.keys(data)
      let len = keys.length
      while(len--) {
        let key = keys[len]
        proxy(vm, "_data", key)
      }
    }
    var sharedPropertyDefinition = {
        enumerable: true,
        configurable: true,
        get: noop,
        set: noop
    };
    function proxy(target, sourceKeys, key) {
      sharedPropertyDefinition.get = function() {
        return this[sourceKeys][key]
      }
      sharedPropertyDefinition.set = function(val) {
        this[sourceKeys][key] = val
      }
      Object.defineProperty(target, key, sharedPropertyDefinition)

    }
    function noop(a, b, c) {}
    function initMethods(vm, methods) {
      for(let key in methods) {
        vm[key] = typeof methods[key] === 'function' ? methods[key].bind(vm) : noop
      }
    }
    let p1 = new Person({
      data: {
        name: 'pino',
        age: 18
      },
      methods: {
        sayName() {
          console.log('I am' + this.name)
        }
      }
    })
    console.log(p1.name) // pino
    p1.sayName() // 'I am pino'