React：PureComponent 和组件原型

Question

Component:

function Component(props, context, updater) {
  this.props = props;
  this.context = context;
  this.refs = emptyObject;
  this.updater = updater || ReactNoopUpdateQueue;
}

PureComponent:

function ComponentDummy() {}
ComponentDummy.prototype = Component.prototype;

function PureComponent(props, context, updater) {
  this.props = props;
  this.context = context;
  this.refs = emptyObject;
  this.updater = updater || ReactNoopUpdateQueue;
}

const pureComponentPrototype = (PureComponent.prototype = new ComponentDummy());
pureComponentPrototype.constructor = PureComponent;
// Avoid an extra prototype jump for these methods.
Object.assign(pureComponentPrototype, Component.prototype);
pureComponentPrototype.isPureReactComponent = true;

I'm really comfused about the ComponentDummy . Why could't us use pureComponent.prototype = {} Could someone explain what the codes below actually do???

const pureComponentPrototype = (PureComponent.prototype = new ComponentDummy());
pureComponentPrototype.constructor = PureComponent;

I really appreciate if you can share me the prototype chain about Component Dummy and PureComponent

Answer 1

Because If We use PureComponent.prototype = new Component() , the function Component will be called, and the props, context, and refs will also be created, which can be lead to take more storage.

But if we use PureComponent.prototype = new ComponentDummy() , we can save that useless storage.

I thought.