vue.ts

import {
  ref,
  ComponentPublicInstance,
  ComponentOptions,
  VNode,
  SetupContext,
  VNodeProps,
  AllowedComponentProps,
  ComponentCustomProps,
  proxyRefs,
  Prop,
  ComponentObjectPropsOptions,
  EmitsOptions,
} from 'vue'
import { VueWithProps } from './props'

function defineGetter<T, K extends keyof T>(
  obj: T,
  key: K,
  getter: () => T[K]
): void {
  Object.defineProperty(obj, key, {
    get: getter,
    enumerable: false,
    configurable: true,
  })
}

function defineProxy(proxy: any, key: string, target: any): void {
  Object.defineProperty(proxy, key, {
    get: () => target[key].value,
    set: (value) => {
      target[key].value = value
    },
    enumerable: true,
    configurable: true,
  })
}

function getSuper(Ctor: typeof VueImpl): typeof VueImpl | undefined {
  const superProto = Object.getPrototypeOf(Ctor.prototype)
  if (!superProto) {
    return undefined
  }

  return superProto.constructor as typeof VueImpl
}

function getOwn<T extends Object, K extends keyof T>(
  value: T,
  key: K
): T[K] | undefined {
  return value.hasOwnProperty(key) ? value[key] : undefined
}

export interface VueStatic {
  // -- Class component configs

  /**
   * @internal
   * The cache of __vccOpts
   */
  __c?: ComponentOptions

  /**
   * @internal
   * The base options specified to this class.
   */
  __b?: ComponentOptions

  /**
   * @internal
   * Component options specified with `@Options` decorator
   */
  __o?: ComponentOptions

  /**
   * @internal
   * Decorators applied to this class.
   */
  __d?: ((options: ComponentOptions) => void)[]

  /**
   * @internal
   * Registered (lifecycle) hooks that will be ported from class methods
   * into component options.
   */
  __h: string[]

  /**
   * @internal
   * Final component options object that Vue core processes.
   * The name must be __vccOpts since it is the contract with the Vue core.
   */
  __vccOpts: ComponentOptions

  // --- Vue Loader etc injections

  /** @internal */
  render?: () => VNode | void

  /** @internal */
  ssrRender?: () => void

  /** @internal */
  __file?: string

  /** @internal */
  __cssModules?: Record<string, any>

  /** @internal */
  __scopeId?: string

  /** @internal */
  __hmrId?: string
}

export type PublicProps = VNodeProps &
  AllowedComponentProps &
  ComponentCustomProps

export type VueBase = Vue<unknown, never[]>

export type VueMixin<V extends VueBase = VueBase> = VueStatic & {
  prototype: V
}

export interface ClassComponentHooks {
  // To be extended on user land

  data?(): object
  beforeCreate?(): void
  created?(): void
  beforeMount?(): void
  mounted?(): void
  beforeUnmount?(): void
  unmounted?(): void
  beforeUpdate?(): void
  updated?(): void
  activated?(): void
  deactivated?(): void
  render?(): VNode | void
  errorCaptured?(err: Error, vm: Vue, info: string): boolean | undefined
  serverPrefetch?(): Promise<unknown>
}

export type Vue<
  Props = unknown,
  Emits extends EmitsOptions = {},
  DefaultProps = {}
> = ComponentPublicInstance<
  Props,
  {},
  {},
  {},
  {},
  Emits,
  PublicProps,
  DefaultProps,
  true
> &
  ClassComponentHooks

export interface VueConstructor<V extends VueBase = Vue> extends VueMixin<V> {
  new (...args: any[]): V

  // --- Public APIs

  registerHooks(keys: string[]): void

  with<P extends { new (): unknown }>(
    Props: P
  ): VueConstructor<V & VueWithProps<InstanceType<P>>>
}

class VueImpl {
  static __h = [
    'data',
    'beforeCreate',
    'created',
    'beforeMount',
    'mounted',
    'beforeUnmount',
    'unmounted',
    'beforeUpdate',
    'updated',
    'activated',
    'deactivated',
    'render',
    'errorCaptured',
    'serverPrefetch',
  ]

  static get __vccOpts(): ComponentOptions {
    // Early return if `this` is base class as it does not have any options
    if (this === Vue) {
      return {}
    }

    const Ctor = this as VueConstructor

    const cache = getOwn(Ctor, '__c')
    if (cache) {
      return cache
    }

    // If the options are provided via decorator use it as a base
    const options: ComponentOptions = { ...getOwn(Ctor, '__o') }
    Ctor.__c = options

    // Handle super class options
    const Super = getSuper(Ctor)
    if (Super) {
      options.extends = Super.__vccOpts
    }

    // Inject base options as a mixin
    const base = getOwn(Ctor, '__b')
    if (base) {
      options.mixins = options.mixins || []
      options.mixins.unshift(base)
    }

    options.methods = { ...options.methods }
    options.computed = { ...options.computed }

    const proto = Ctor.prototype
    Object.getOwnPropertyNames(proto).forEach((key) => {
      if (key === 'constructor') {
        return
      }

      // hooks
      if (Ctor.__h.indexOf(key) > -1) {
        ;(options as any)[key] = (proto as any)[key]
        return
      }

      const descriptor = Object.getOwnPropertyDescriptor(proto, key)!

      // methods
      if (typeof descriptor.value === 'function') {
        ;(options.methods as any)[key] = descriptor.value
        return
      }

      // computed properties
      if (descriptor.get || descriptor.set) {
        ;(options.computed as any)[key] = {
          get: descriptor.get,
          set: descriptor.set,
        }
        return
      }
    })

    options.setup = function (props: Record<string, any>, ctx: SetupContext) {
      const data: any = new Ctor(props, ctx)
      const dataKeys = Object.keys(data)

      const plainData: any = {}
      let promise: Promise<any> | null = null

      // Initialize reactive data and convert constructor `this` to a proxy
      dataKeys.forEach((key) => {
        // Skip if the value is undefined not to make it reactive.
        // If the value has `__s`, it's a value from `setup` helper, proceed it later.
        if (data[key] === undefined || (data[key] && data[key].__s)) {
          return
        }

        plainData[key] = ref(data[key])
        defineProxy(data, key, plainData)
      })

      // Invoke composition functions
      dataKeys.forEach((key) => {
        if (data[key] && data[key].__s) {
          const setupState = data[key].__s()
          if (setupState instanceof Promise) {
            if (!promise) {
              promise = Promise.resolve(plainData)
            }
            promise = promise.then(() => {
              return setupState.then((value) => {
                plainData[key] = proxyRefs(value)
                return plainData
              })
            })
          } else {
            plainData[key] = proxyRefs(setupState)
          }
        }
      })

      return promise ?? plainData
    }

    const decorators = getOwn(Ctor, '__d')
    if (decorators) {
      decorators.forEach((fn) => fn(options))
    }

    // from Vue Loader
    const injections = [
      'render',
      'ssrRender',
      '__file',
      '__cssModules',
      '__scopeId',
      '__hmrId',
    ]
    injections.forEach((key) => {
      if ((Ctor as any)[key]) {
        options[key] = (Ctor as any)[key]
      }
    })

    return options
  }

  static registerHooks(keys: string[]): void {
    this.__h.push(...keys)
  }

  static with(Props: { new (): unknown }): VueConstructor {
    const propsMeta = new Props() as Record<string, Prop<any> | undefined>
    const props: ComponentObjectPropsOptions = {}

    Object.keys(propsMeta).forEach((key) => {
      const meta = propsMeta[key]
      props[key] = meta ?? null
    })

    class PropsMixin extends this {
      static __b: ComponentOptions = {
        props,
      }
    }
    return PropsMixin as VueConstructor
  }

  $props!: Record<string, any>
  $emit!: (event: string, ...args: any[]) => void
  $attrs!: ComponentPublicInstance['$attrs']
  $slots!: ComponentPublicInstance['$slots']

  constructor(props: Record<string, any>, ctx: SetupContext) {
    defineGetter(this, '$props', () => props)
    defineGetter(this, '$attrs', () => ctx.attrs)
    defineGetter(this, '$slots', () => ctx.slots)
    defineGetter(this, '$emit', () => ctx.emit)

    Object.keys(props).forEach((key) => {
      Object.defineProperty(this, key, {
        enumerable: false,
        configurable: true,
        writable: true,
        value: (props as any)[key],
      })
    })
  }
}

export const Vue: VueConstructor = VueImpl as VueConstructor