All files / runtime-dom/src apiCustomElement.ts

90.7% Statements 371/409
90.78% Branches 138/152
96.77% Functions 30/31
90.7% Lines 371/409

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 7102x                                                                 2x                 2x 2x     2x                                                                                                                                                                                                                                             2x 2x 50x 50x       50x 50x 50x 50x 50x 50x 50x 69x 69x 50x   50x 50x   2x 2x               2x 2x         2x 2x   2x 2x       2x       2x               2x             2x 2x 2x 2x                     2x     2x         69x 69x 69x 69x 69x 69x   69x 69x           69x 63x 63x 69x 6x 6x 69x   69x   58x 58x 69x   2x   74x   74x 6x 6x 72x     72x 72x 74x 74x 257x 15x 15x 15x 257x   74x 70x 1x 1x 70x 69x 3x 3x 3x 3x 69x 66x 66x 69x 70x 74x   2x 72x 15x 15x 15x 72x   2x 70x 70x 70x 66x 65x 65x 65x   66x 66x 66x 66x 70x 70x         2x 69x         69x 19x 19x     69x 33x 34x 34x 69x   69x   69x 69x 69x   69x     69x 69x 21x 34x 34x 5x 4x 4x 5x 5x 5x 5x 34x 21x 69x   69x     11x 11x     69x 63x 69x               69x 69x   69x 69x 11x 11x 11x 69x 58x 58x 69x   2x 69x   48x 48x 69x 69x 1x 1x 69x 69x     69x 69x 68x 3x   2x   2x 2x 3x 1x 1x 3x 69x   2x 69x 69x     69x 913x 4x 4x 913x     69x 40x 40x 5x 5x 40x 16x 16x 40x 40x 69x   2x 53x 47x 53x 53x 53x 2x 2x 47x 53x         2x 5x 5x         2x 73x 73x 73x 73x 73x 73x 52x 3x 52x 49x   49x     49x 52x 20x 20x   52x 25x 1x 25x 20x 24x 1x 1x 25x 52x 73x   2x 22x 22x   2x 91x 91x 6x 6x 6x 91x 91x 71x 71x 71x 71x   71x 71x   1x 1x 1x 1x 1x 1x 1x 1x 71x   71x 12x 12x 12x 12x 1x 11x 12x 12x 12x     71x     11x 11x 1x 1x 11x   71x 71x 71x 91x 91x   2x 143x 143x 143x 143x 143x 13x 10x 10x 3x 3x 10x 142x 13x 13x 13x 13x   13x 13x 5x 5x 5x 5x 1x 1x 5x 5x 13x 8x 8x 13x 13x 143x         2x 6x 6x 6x 7x 7x 7x 7x 7x 6x         2x 7x 7x 7x 7x 7x 7x 7x 7x 6x   7x                 7x 7x 7x 1x 1x 7x 7x 7x         2x 79x 79x         2x 4x 4x 4x   4x 4x 4x 4x 4x 4x 4x 4x 2x   2x 2x 2x 2x 2x 2x                                     2x 1x 1x 1x  
import {
  type App,
  type Component,
  type ComponentCustomElementInterface,
  type ComponentInjectOptions,
  type ComponentInternalInstance,
  type ComponentObjectPropsOptions,
  type ComponentOptions,
  type ComponentOptionsBase,
  type ComponentOptionsMixin,
  type ComponentProvideOptions,
  type ComponentPublicInstance,
  type ComputedOptions,
  type ConcreteComponent,
  type CreateAppFunction,
  type CreateComponentPublicInstanceWithMixins,
  type DefineComponent,
  type Directive,
  type EmitsOptions,
  type EmitsToProps,
  type ExtractPropTypes,
  type MethodOptions,
  type RenderFunction,
  type SetupContext,
  type SlotsType,
  type VNode,
  type VNodeProps,
  createVNode,
  defineComponent,
  getCurrentInstance,
  nextTick,
  unref,
  warn,
} from '@vue/runtime-core'
import {
  camelize,
  extend,
  hasOwn,
  hyphenate,
  isArray,
  isPlainObject,
  toNumber,
} from '@vue/shared'
import { createApp, createSSRApp, render } from '.'
 
// marker for attr removal
const REMOVAL = {}
 
export type VueElementConstructor<P = {}> = {
  new (initialProps?: Record<string, any>): VueElement & P
}
 
export interface CustomElementOptions {
  styles?: string[]
  shadowRoot?: boolean
  nonce?: string
  configureApp?: (app: App) => void
}
 
// defineCustomElement provides the same type inference as defineComponent
// so most of the following overloads should be kept in sync w/ defineComponent.
 
// overload 1: direct setup function
export function defineCustomElement<Props, RawBindings = object>(
  setup: (props: Props, ctx: SetupContext) => RawBindings | RenderFunction,
  options?: Pick<ComponentOptions, 'name' | 'inheritAttrs' | 'emits'> &
    CustomElementOptions & {
      props?: (keyof Props)[]
    },
): VueElementConstructor<Props>
export function defineCustomElement<Props, RawBindings = object>(
  setup: (props: Props, ctx: SetupContext) => RawBindings | RenderFunction,
  options?: Pick<ComponentOptions, 'name' | 'inheritAttrs' | 'emits'> &
    CustomElementOptions & {
      props?: ComponentObjectPropsOptions<Props>
    },
): VueElementConstructor<Props>
 
// overload 2: defineCustomElement with options object, infer props from options
export function defineCustomElement<
  // props
  RuntimePropsOptions extends
    ComponentObjectPropsOptions = ComponentObjectPropsOptions,
  PropsKeys extends string = string,
  // emits
  RuntimeEmitsOptions extends EmitsOptions = {},
  EmitsKeys extends string = string,
  // other options
  Data = {},
  SetupBindings = {},
  Computed extends ComputedOptions = {},
  Methods extends MethodOptions = {},
  Mixin extends ComponentOptionsMixin = ComponentOptionsMixin,
  Extends extends ComponentOptionsMixin = ComponentOptionsMixin,
  InjectOptions extends ComponentInjectOptions = {},
  InjectKeys extends string = string,
  Slots extends SlotsType = {},
  LocalComponents extends Record<string, Component> = {},
  Directives extends Record<string, Directive> = {},
  Exposed extends string = string,
  Provide extends ComponentProvideOptions = ComponentProvideOptions,
  // resolved types
  InferredProps = string extends PropsKeys
    ? ComponentObjectPropsOptions extends RuntimePropsOptions
      ? {}
      : ExtractPropTypes<RuntimePropsOptions>
    : { [key in PropsKeys]?: any },
  ResolvedProps = InferredProps & EmitsToProps<RuntimeEmitsOptions>,
>(
  options: CustomElementOptions & {
    props?: (RuntimePropsOptions & ThisType<void>) | PropsKeys[]
  } & ComponentOptionsBase<
      ResolvedProps,
      SetupBindings,
      Data,
      Computed,
      Methods,
      Mixin,
      Extends,
      RuntimeEmitsOptions,
      EmitsKeys,
      {}, // Defaults
      InjectOptions,
      InjectKeys,
      Slots,
      LocalComponents,
      Directives,
      Exposed,
      Provide
    > &
    ThisType<
      CreateComponentPublicInstanceWithMixins<
        Readonly<ResolvedProps>,
        SetupBindings,
        Data,
        Computed,
        Methods,
        Mixin,
        Extends,
        RuntimeEmitsOptions,
        EmitsKeys,
        {},
        false,
        InjectOptions,
        Slots,
        LocalComponents,
        Directives,
        Exposed
      >
    >,
  extraOptions?: CustomElementOptions,
): VueElementConstructor<ResolvedProps>
 
// overload 3: defining a custom element from the returned value of
// `defineComponent`
export function defineCustomElement<
  // this should be `ComponentPublicInstanceConstructor` but that type is not exported
  T extends { new (...args: any[]): ComponentPublicInstance<any> },
>(
  options: T,
  extraOptions?: CustomElementOptions,
): VueElementConstructor<
  T extends DefineComponent<infer P, any, any, any> ? P : unknown
>
 
/*! #__NO_SIDE_EFFECTS__ */
export function defineCustomElement(
  options: any,
  extraOptions?: ComponentOptions,
  /**
   * @internal
   */
  _createApp?: CreateAppFunction<Element>,
): VueElementConstructor {
  const Comp = defineComponent(options, extraOptions) as any
  if (isPlainObject(Comp)) extend(Comp, extraOptions)
  class VueCustomElement extends VueElement {
    static def = Comp
    constructor(initialProps?: Record<string, any>) {
      super(Comp, initialProps, _createApp)
    }
  }
 
  return VueCustomElement
}
 
/*! #__NO_SIDE_EFFECTS__ */
export const defineSSRCustomElement = ((
  options: any,
  extraOptions?: ComponentOptions,
) => {
  // @ts-expect-error
  return defineCustomElement(options, extraOptions, createSSRApp)
}) as typeof defineCustomElement
 
const BaseClass = (
  typeof HTMLElement !== 'undefined' ? HTMLElement : class {}
) as typeof HTMLElement
 
type InnerComponentDef = ConcreteComponent & CustomElementOptions
 
export class VueElement
  extends BaseClass
  implements ComponentCustomElementInterface
{
  _isVueCE = true
  /**
   * @internal
   */
  _instance: ComponentInternalInstance | null = null
  /**
   * @internal
   */
  _app: App | null = null
  /**
   * @internal
   */
  _root: Element | ShadowRoot
  /**
   * @internal
   */
  _nonce: string | undefined = this._def.nonce
 
  /**
   * @internal
   */
  _teleportTarget?: HTMLElement
 
  private _connected = false
  private _resolved = false
  private _numberProps: Record<string, true> | null = null
  private _styleChildren = new WeakSet()
  private _pendingResolve: Promise<void> | undefined
  private _parent: VueElement | undefined
  /**
   * dev only
   */
  private _styles?: HTMLStyleElement[]
  /**
   * dev only
   */
  private _childStyles?: Map<string, HTMLStyleElement[]>
  private _ob?: MutationObserver | null = null
  private _slots?: Record<string, Node[]>
 
  constructor(
    /**
     * Component def - note this may be an AsyncWrapper, and this._def will
     * be overwritten by the inner component when resolved.
     */
    private _def: InnerComponentDef,
    private _props: Record<string, any> = {},
    private _createApp: CreateAppFunction<Element> = createApp,
  ) {
    super()
    if (this.shadowRoot && _createApp !== createApp) {
      this._root = this.shadowRoot
    } else {
      if (__DEV__ && this.shadowRoot) {
        warn(
          `Custom element has pre-rendered declarative shadow root but is not ` +
            `defined as hydratable. Use \`defineSSRCustomElement\`.`,
        )
      }
      if (_def.shadowRoot !== false) {
        this.attachShadow({ mode: 'open' })
        this._root = this.shadowRoot!
      } else {
        this._root = this
      }
    }
 
    if (!(this._def as ComponentOptions).__asyncLoader) {
      // for sync component defs we can immediately resolve props
      this._resolveProps(this._def)
    }
  }
 
  connectedCallback(): void {
    // avoid resolving component if it's not connected
    if (!this.isConnected) return
 
    if (!this.shadowRoot) {
      this._parseSlots()
    }
    this._connected = true
 
    // locate nearest Vue custom element parent for provide/inject
    let parent: Node | null = this
    while (
      (parent = parent && (parent.parentNode || (parent as ShadowRoot).host))
    ) {
      if (parent instanceof VueElement) {
        this._parent = parent
        break
      }
    }
 
    if (!this._instance) {
      if (this._resolved) {
        this._setParent()
        this._update()
      } else {
        if (parent && parent._pendingResolve) {
          this._pendingResolve = parent._pendingResolve.then(() => {
            this._pendingResolve = undefined
            this._resolveDef()
          })
        } else {
          this._resolveDef()
        }
      }
    }
  }
 
  private _setParent(parent = this._parent) {
    if (parent) {
      this._instance!.parent = parent._instance
      this._instance!.provides = parent._instance!.provides
    }
  }
 
  disconnectedCallback(): void {
    this._connected = false
    nextTick(() => {
      if (!this._connected) {
        if (this._ob) {
          this._ob.disconnect()
          this._ob = null
        }
        // unmount
        this._app && this._app.unmount()
        if (this._instance) this._instance.ce = undefined
        this._app = this._instance = null
      }
    })
  }
 
  /**
   * resolve inner component definition (handle possible async component)
   */
  private _resolveDef() {
    if (this._pendingResolve) {
      return
    }
 
    // set initial attrs
    for (let i = 0; i < this.attributes.length; i++) {
      this._setAttr(this.attributes[i].name)
    }
 
    // watch future attr changes
    this._ob = new MutationObserver(mutations => {
      for (const m of mutations) {
        this._setAttr(m.attributeName!)
      }
    })
 
    this._ob.observe(this, { attributes: true })
 
    const resolve = (def: InnerComponentDef, isAsync = false) => {
      this._resolved = true
      this._pendingResolve = undefined
 
      const { props, styles } = def
 
      // cast Number-type props set before resolve
      let numberProps
      if (props && !isArray(props)) {
        for (const key in props) {
          const opt = props[key]
          if (opt === Number || (opt && opt.type === Number)) {
            if (key in this._props) {
              this._props[key] = toNumber(this._props[key])
            }
            ;(numberProps || (numberProps = Object.create(null)))[
              camelize(key)
            ] = true
          }
        }
      }
      this._numberProps = numberProps
 
      if (isAsync) {
        // defining getter/setters on prototype
        // for sync defs, this already happened in the constructor
        this._resolveProps(def)
      }
 
      // apply CSS
      if (this.shadowRoot) {
        this._applyStyles(styles)
      } else if (__DEV__ && styles) {
        warn(
          'Custom element style injection is not supported when using ' +
            'shadowRoot: false',
        )
      }
 
      // initial mount
      this._mount(def)
    }
 
    const asyncDef = (this._def as ComponentOptions).__asyncLoader
    if (asyncDef) {
      this._pendingResolve = asyncDef().then(def =>
        resolve((this._def = def), true),
      )
    } else {
      resolve(this._def)
    }
  }
 
  private _mount(def: InnerComponentDef) {
    if ((__DEV__ || __FEATURE_PROD_DEVTOOLS__) && !def.name) {
      // @ts-expect-error
      def.name = 'VueElement'
    }
    this._app = this._createApp(def)
    if (def.configureApp) {
      def.configureApp(this._app)
    }
    this._app._ceVNode = this._createVNode()
    this._app.mount(this._root)
 
    // apply expose after mount
    const exposed = this._instance && this._instance.exposed
    if (!exposed) return
    for (const key in exposed) {
      if (!hasOwn(this, key)) {
        // exposed properties are readonly
        Object.defineProperty(this, key, {
          // unwrap ref to be consistent with public instance behavior
          get: () => unref(exposed[key]),
        })
      } else if (__DEV__) {
        warn(`Exposed property "${key}" already exists on custom element.`)
      }
    }
  }
 
  private _resolveProps(def: InnerComponentDef) {
    const { props } = def
    const declaredPropKeys = isArray(props) ? props : Object.keys(props || {})
 
    // check if there are props set pre-upgrade or connect
    for (const key of Object.keys(this)) {
      if (key[0] !== '_' && declaredPropKeys.includes(key)) {
        this._setProp(key, this[key as keyof this])
      }
    }
 
    // defining getter/setters on prototype
    for (const key of declaredPropKeys.map(camelize)) {
      Object.defineProperty(this, key, {
        get() {
          return this._getProp(key)
        },
        set(val) {
          this._setProp(key, val, true, true)
        },
      })
    }
  }
 
  protected _setAttr(key: string): void {
    if (key.startsWith('data-v-')) return
    const has = this.hasAttribute(key)
    let value = has ? this.getAttribute(key) : REMOVAL
    const camelKey = camelize(key)
    if (has && this._numberProps && this._numberProps[camelKey]) {
      value = toNumber(value)
    }
    this._setProp(camelKey, value, false, true)
  }
 
  /**
   * @internal
   */
  protected _getProp(key: string): any {
    return this._props[key]
  }
 
  /**
   * @internal
   */
  _setProp(
    key: string,
    val: any,
    shouldReflect = true,
    shouldUpdate = false,
  ): void {
    if (val !== this._props[key]) {
      if (val === REMOVAL) {
        delete this._props[key]
      } else {
        this._props[key] = val
        // support set key on ceVNode
        if (key === 'key' && this._app) {
          this._app._ceVNode!.key = val
        }
      }
      if (shouldUpdate && this._instance) {
        this._update()
      }
      // reflect
      if (shouldReflect) {
        if (val === true) {
          this.setAttribute(hyphenate(key), '')
        } else if (typeof val === 'string' || typeof val === 'number') {
          this.setAttribute(hyphenate(key), val + '')
        } else if (!val) {
          this.removeAttribute(hyphenate(key))
        }
      }
    }
  }
 
  private _update() {
    render(this._createVNode(), this._root)
  }
 
  private _createVNode(): VNode<any, any> {
    const baseProps: VNodeProps = {}
    if (!this.shadowRoot) {
      baseProps.onVnodeMounted = baseProps.onVnodeUpdated =
        this._renderSlots.bind(this)
    }
    const vnode = createVNode(this._def, extend(baseProps, this._props))
    if (!this._instance) {
      vnode.ce = instance => {
        this._instance = instance
        instance.ce = this
        instance.isCE = true // for vue-i18n backwards compat
        // HMR
        if (__DEV__) {
          instance.ceReload = newStyles => {
            // always reset styles
            if (this._styles) {
              this._styles.forEach(s => this._root.removeChild(s))
              this._styles.length = 0
            }
            this._applyStyles(newStyles)
            this._instance = null
            this._update()
          }
        }
 
        const dispatch = (event: string, args: any[]) => {
          this.dispatchEvent(
            new CustomEvent(
              event,
              isPlainObject(args[0])
                ? extend({ detail: args }, args[0])
                : { detail: args },
            ),
          )
        }
 
        // intercept emit
        instance.emit = (event: string, ...args: any[]) => {
          // dispatch both the raw and hyphenated versions of an event
          // to match Vue behavior
          dispatch(event, args)
          if (hyphenate(event) !== event) {
            dispatch(hyphenate(event), args)
          }
        }
 
        this._setParent()
      }
    }
    return vnode
  }
 
  private _applyStyles(
    styles: string[] | undefined,
    owner?: ConcreteComponent,
  ) {
    if (!styles) return
    if (owner) {
      if (owner === this._def || this._styleChildren.has(owner)) {
        return
      }
      this._styleChildren.add(owner)
    }
    const nonce = this._nonce
    for (let i = styles.length - 1; i >= 0; i--) {
      const s = document.createElement('style')
      if (nonce) s.setAttribute('nonce', nonce)
      s.textContent = styles[i]
      this.shadowRoot!.prepend(s)
      // record for HMR
      if (__DEV__) {
        if (owner) {
          if (owner.__hmrId) {
            if (!this._childStyles) this._childStyles = new Map()
            let entry = this._childStyles.get(owner.__hmrId)
            if (!entry) {
              this._childStyles.set(owner.__hmrId, (entry = []))
            }
            entry.push(s)
          }
        } else {
          ;(this._styles || (this._styles = [])).push(s)
        }
      }
    }
  }
 
  /**
   * Only called when shadowRoot is false
   */
  private _parseSlots() {
    const slots: VueElement['_slots'] = (this._slots = {})
    let n
    while ((n = this.firstChild)) {
      const slotName =
        (n.nodeType === 1 && (n as Element).getAttribute('slot')) || 'default'
      ;(slots[slotName] || (slots[slotName] = [])).push(n)
      this.removeChild(n)
    }
  }
 
  /**
   * Only called when shadowRoot is false
   */
  private _renderSlots() {
    const outlets = (this._teleportTarget || this).querySelectorAll('slot')
    const scopeId = this._instance!.type.__scopeId
    for (let i = 0; i < outlets.length; i++) {
      const o = outlets[i] as HTMLSlotElement
      const slotName = o.getAttribute('name') || 'default'
      const content = this._slots![slotName]
      const parent = o.parentNode!
      if (content) {
        for (const n of content) {
          // for :slotted css
          if (scopeId && n.nodeType === 1) {
            const id = scopeId + '-s'
            const walker = document.createTreeWalker(n, 1)
            ;(n as Element).setAttribute(id, '')
            let child
            while ((child = walker.nextNode())) {
              ;(child as Element).setAttribute(id, '')
            }
          }
          parent.insertBefore(n, o)
        }
      } else {
        while (o.firstChild) parent.insertBefore(o.firstChild, o)
      }
      parent.removeChild(o)
    }
  }
 
  /**
   * @internal
   */
  _injectChildStyle(comp: ConcreteComponent & CustomElementOptions): void {
    this._applyStyles(comp.styles, comp)
  }
 
  /**
   * @internal
   */
  _removeChildStyle(comp: ConcreteComponent): void {
    if (__DEV__) {
      this._styleChildren.delete(comp)
      if (this._childStyles && comp.__hmrId) {
        // clear old styles
        const oldStyles = this._childStyles.get(comp.__hmrId)
        if (oldStyles) {
          oldStyles.forEach(s => this._root.removeChild(s))
          oldStyles.length = 0
        }
      }
    }
  }
}
 
export function useHost(caller?: string): VueElement | null {
  const instance = getCurrentInstance()
  const el = instance && (instance.ce as VueElement)
  if (el) {
    return el
  } else if (__DEV__) {
    if (!instance) {
      warn(
        `${caller || 'useHost'} called without an active component instance.`,
      )
    } else {
      warn(
        `${caller || 'useHost'} can only be used in components defined via ` +
          `defineCustomElement.`,
      )
    }
  }
  return null
}
 
/**
 * Retrieve the shadowRoot of the current custom element. Only usable in setup()
 * of a `defineCustomElement` component.
 */
export function useShadowRoot(): ShadowRoot | null {
  const el = __DEV__ ? useHost('useShadowRoot') : useHost()
  return el && el.shadowRoot
}