inject和provide源码

inject和provide的使用方法，点击链接查看

在初始化时，执行了下面

 callHook(vm, 'beforeCreate');
 initInjections(vm); // resolve injections before data/props
 initState(vm);
 initProvide(vm); // resolve provide after data/props
 callHook(vm, 'created');

1.initInjections 函数

  function initInjections (vm) {
    var result = resolveInject(vm.$options.inject, vm);
    if (result) {
     Object.keys(result).forEach(function (key) {
        {
          defineReactive$$1(vm, key, result[key], function () {警告不允许改});
        }
      });
    }
  }

2.resolveInject函数

function resolveInject (inject, vm) {
  if (inject) {
    var result = Object.create(null);
    var keys = Reflect.ownKeys(inject)
    for (var i = 0; i < keys.length; i++) {
      var key = keys[i];
      if (key === '__ob__') { continue }
      var provideKey = inject[key].from;
      var source = vm;
      while (source) {
        if (source._provided && hasOwn(source._provided, provideKey)) {
          result[key] = source._provided[provideKey];
          break
        }
        source = source.$parent;
      }
      if (!source) {
        if ('default' in inject[key]) {
          var provideDefault = inject[key].default;
          result[key] = typeof provideDefault === 'function'
            ? provideDefault.call(vm)
            : provideDefault;
        } else {
          warn(("Injection \"" + key + "\" not found"), vm);
        }
      }
    }
    return result
  }
}

1.initProvide函数

function initProvide (vm) {
  var provide = vm.$options.provide;
  if (provide) {
    vm._provided = typeof provide === 'function'
      ? provide.call(vm)
      : provide;
  }
}