今天给大家分享Vue初始化中的选项合并之initInternalComponent的相关知识，具体代码如下所示：
export function initInternalComponent (vm: Component, options: InternalComponentOptions) {
const opts = vm.$options = Object.create(vm.constructor.options)
// doing this because it's faster than dynamic enumeration.
const parentVnode = options._parentVnode
opts.parent = options.parent
opts._parentVnode = parentVnode

const vnodeComponentOptions = parentVnode.componentOptions
opts.propsData = vnodeComponentOptions.propsData
opts._parentListeners = vnodeComponentOptions.listeners
opts._renderChildren = vnodeComponentOptions.children
opts._componentTag = vnodeComponentOptions.tag

if (options.render) {

opts.render = options.render

opts.staticRenderFns = options.staticRenderFns
}
}
export function initInternalComponent (vm: Component, options: InternalComponentOptions) {
const opts = vm.$options = Object.create(vm.constructor.options)
// doing this because it's faster than dynamic enumeration.
const parentVnode = options._parentVnode
opts.parent = options.parent
opts._parentVnode = parentVnode

const vnodeComponentOptions = parentVnode.componentOptions
opts.propsData = vnodeComponentOptions.propsData
opts._parentListeners = vnodeComponentOptions.listeners
opts._renderChildren = vnodeComponentOptions.children
opts._componentTag = vnodeComponentOptions.tag

if (options.render) {

opts.render = options.render

opts.staticRenderFns = options.staticRenderFns
}
}initInternalComponent方法接受两个参数，第一个参数是组件实例，即this。第二个参数是组件构造函数中传入的option，这个option根据上文的分析，他是在createComponentInstanceForVnode方法中定义的：initInternalComponentcreateComponentInstanceForVnode
export function createComponentInstanceForVnode (
vnode: any, // we know it's MountedComponentVNode but flow doesn't
parent: any, // activeInstance in lifecycle state
): Component {
const options: InternalComponentOptions = {

_isComponent: true,

_parentVnode: vnode,

parent
}
// check inline-template render functions
const inlineTemplate = vnode.data.inlineTemplate
if (isDef(inlineTemplate)) {

options.render = inlineTemplate.render

options.staticRenderFns = inlineTemplate.staticRenderFns
}
return new vnode.componentOptions.Ctor(options)
}
export function createComponentInstanceForVnode (
vnode: any, // we know it's MountedComponentVNode but flow doesn't
parent: any, // activeInstance in lifecycle state
): Component {
const options: InternalComponentOptions = {

_isComponent: true,

_parentVnode: vnode,

parent
}
// check inline-template render functions
const inlineTemplate = vnode.data.inlineTemplate
if (isDef(inlineTemplate)) {

options.render = inlineTemplate.render

options.staticRenderFns = inlineTemplate.staticRenderFns
}
return new vnode.componentOptions.Ctor(options)
}option中有三个属性值，_isComponent上面已经提到过了；_parentVode其实就是该组件实例的vnode对象（createComponentInstanceForVnode就是根据这个vnode对象去创建一个组件实例）；parent则是该组件的父组件实例对象。
然后我们来看看具体initInternalComponent做了什么操作:_isComponent_parentVodecreateComponentInstanceForVnodeparentinitInternalComponent
const opts = vm.$options = Object.create(vm.constructor.options)
const opts = vm.$options = Object.create(vm.constructor.options)首先，用Object.create这个函数，把组件构造函数的options挂载到vm.$options的__proto__上。Object.createoptionsvm.$options__proto__
const parentVnode = options._parentVnode
opts.parent = options.parent
opts._parentVnode = parentVnode
const parentVnode = options._parentVnode
opts.parent = options.parent
opts._parentVnode = parentVnode接下把传入参数的option的_parentVode和parent挂载到组件实例$options上。用我们在两种策略里的那个例子来说，parent就是我们组件的根实例，而_parentVnode就是生成的一个Vnode对象。_parentVodeparent$optionsparent_parentVnode
const vnodeComponentOptions = parentVnode.componentOptions
opts.propsData = vnodeComponentOptions.propsData
opts._parentListeners = vnodeComponentOptions.listeners
opts._renderChildren = vnodeComponentOptions.children
opts._componentTag = vnodeComponentOptions.tag
const vnodeComponentOptions = parentVnode.componentOptions
opts.propsData = vnodeComponentOptions.propsData
opts._parentListeners = vnodeComponentOptions.listeners
opts._renderChildren = vnodeComponentOptions.children
opts._componentTag = vnodeComponentOptions.tag然后把父组件里的vnode上的四个属性挂载到我们的$options上，还是用那个例子来说，propsData就是根据:msg="msg"生成的，他的值就是在根组件里定义的那个msg{msg: "props-message"}。而_parentListeners就是根据@log-msg="logMsg"生成的，他的值是logMsg这个定义在父组件中的方法。$optionspropsData:msg="msg"{msg: "props-message"}_parentListeners@log-msg="logMsg"logMsg
if (options.render) {

opts.render = options.render

opts.staticRenderFns = options.staticRenderFns
}
if (options.render) {

opts.render = options.render

opts.staticRenderFns = options.staticRenderFns
}最后就是如果传入的option中如果有render，把render相关的也挂载到$options上。
因此，这个initInternalComponent主要做了两件事情：1.指定组件$options原型，2.把组件依赖于父组件的props、listeners也挂载到options上，方便子组件调用。initInternalComponent总结总结总结