element-plus/packages/utils/props.ts

import mapValues from 'lodash/mapValues'
import { debugWarn } from './error'
import type { ExtractPropTypes, PropType } from '@vue/runtime-core'
import type { Mutable } from './types'

const wrapperKey = Symbol()
export type PropWrapper<T> = { [wrapperKey]: T }

type ResolveProp<T> = ExtractPropTypes<{
  key: { type: T; required: true }
}>['key']
type ResolvePropType<T> = ResolveProp<T> extends { type: infer V }
  ? V
  : ResolveProp<T>
type ResolvePropTypeWithReadonly<T> = Readonly<T> extends Readonly<
  Array<infer A>
>
  ? ResolvePropType<A[]>
  : ResolvePropType<T>

type BuildPropOption<T, D, R, V, C> = {
  type?: T
  values?: readonly V[]
  required?: R
  default?: R extends true
    ? never
    : D extends Record<string, unknown> | Array<any>
    ? () => D
    : D
  validator?: ((val: any) => val is C) | ((val: any) => boolean)
}

type IfUnknown<T, V> = [unknown] extends T ? V : T

type BuildPropType<T, V, C> =
  | (T extends PropWrapper<unknown>
      ? T[typeof wrapperKey]
      : [V] extends [never]
      ? ResolvePropTypeWithReadonly<T>
      : never)
  | V
  | C

type BuildPropDefault<D, R> = R extends true
  ? { readonly default?: undefined }
  : {
      readonly default: Exclude<D, undefined> extends never
        ? undefined
        : Exclude<
            D extends Record<string, unknown> | Array<any> ? () => D : D,
            undefined
          >
    }
type BuildPropReturn<T, D, R, V, C> = {
  readonly type: PropType<
    BuildPropType<IfUnknown<T, never>, IfUnknown<V, never>, IfUnknown<C, never>>
  >
  readonly required: IfUnknown<R, false>
  readonly validator: ((val: unknown) => boolean) | undefined
} & BuildPropDefault<IfUnknown<D, never>, IfUnknown<R, false>>

/**
 * @description Build prop. It can better optimize prop types
 * @description 生成 prop，能更好地优化类型
 * @example
  // limited options
  // the type will be PropType<'light' | 'dark'>
  buildProp({
    type: String,
    values: ['light', 'dark'],
  } as const)
  * @example
  // limited options and other types
  // the type will be PropType<'small' | 'medium' | number>
  buildProp({
    type: [String, Number],
    values: ['small', 'medium'],
    validator: (val: unknown): val is number => typeof val === 'number',
  } as const)
  @link see more: https://github.com/element-plus/element-plus/pull/3341
 */
export function buildProp<
  T = never,
  D extends
    | (T extends PropWrapper<any>
        ? T[typeof wrapperKey]
        : ResolvePropTypeWithReadonly<T>)
    | V = never,
  R extends boolean = false,
  V = never,
  C = never
>(option: BuildPropOption<T, D, R, V, C> = {}) {
  const { values, required, default: defaultValue, type, validator } = option

  const _validator =
    values || validator
      ? (val: unknown) => {
          let valid = false
          let allowedValues: unknown[] = []

          if (values) {
            allowedValues = [...values, defaultValue]
            valid ||= allowedValues.includes(val)
          }
          if (validator) valid ||= validator(val)

          if (!valid && allowedValues.length > 0) {
            debugWarn(
              `Vue warn`,
              `Invalid prop: Expected one of (${allowedValues.join(
                ', '
              )}), got value ${val}`
            )
          }
          return valid
        }
      : undefined

  return {
    type: (type as any)?.[wrapperKey] || type,
    required: !!required,
    default: defaultValue,
    validator: _validator,
  } as unknown as BuildPropReturn<T, D, R, V, C>
}

export const buildProps = <
  O extends Record<string, BuildPropOption<any, any, any, any, any>>
>(
  options: O
) =>
  mapValues(options, (option) => buildProp(option)) as unknown as {
    [K in keyof O]: O[K] extends BuildPropOption<
      infer T,
      infer D,
      infer R,
      infer V,
      infer C
    >
      ? BuildPropReturn<T, D, R, V, C>
      : never
  }

export const definePropType = <T>(val: any) =>
  ({ [wrapperKey]: val } as PropWrapper<T>)

export const keyOf = <T>(arr: T) => Object.keys(arr) as Array<keyof T>
export const mutable = <T extends readonly any[] | Record<string, unknown>>(
  val: T
) => val as Mutable<typeof val>

export const componentSize = ['large', 'medium', 'small', 'mini'] as const