vue#createTextVNode TypeScript Examples

/**
 *
 * @param library - A library of concrete components to use
 * @param schema -
 * @returns
 */
function parseSchema(
  library: FormKitComponentLibrary,
  schema: FormKitSchemaNode | FormKitSchemaNode[]
): SchemaProvider {
  /**
   * Given an if/then/else schema node, pre-compile the node and return the
   * artifacts for the render function.
   * @param data - The schema context object
   * @param library - The available components
   * @param node - The node to parse
   */
  function parseCondition(
    library: FormKitComponentLibrary,
    node: FormKitSchemaCondition
  ): [RenderContent[0], RenderContent[3], RenderContent[4]] {
    const condition = provider(compile(node.if), { if: true })
    const children = createElements(library, node.then)
    const alternate = node.else ? createElements(library, node.else) : null
    return [condition, children, alternate]
  }

  /**
   * Parses a conditional if/then/else attribute statement.
   * @param data - The data object
   * @param attr - The attribute
   * @param _default - The default value
   * @returns
   */
  function parseConditionAttr(
    attr: FormKitSchemaAttributesCondition,
    _default: FormKitAttributeValue
  ): () => FormKitAttributeValue | FormKitSchemaAttributes {
    const condition = provider(compile(attr.if))
    let b: () => FormKitAttributeValue = () => _default
    let a: () => FormKitAttributeValue = () => _default

    if (typeof attr.then === 'object') {
      a = parseAttrs(attr.then, undefined)
    } else if (typeof attr.then === 'string' && attr.then?.startsWith('$')) {
      a = provider(compile(attr.then))
    } else {
      a = () => attr.then
    }

    if (has(attr, 'else')) {
      if (typeof attr.else === 'object') {
        b = parseAttrs(attr.else)
      } else if (typeof attr.else === 'string' && attr.else?.startsWith('$')) {
        b = provider(compile(attr.else))
      } else {
        b = () => attr.else
      }
    }
    return () => (condition() ? a() : b())
  }

  /**
   * Parse attributes for dynamic content.
   * @param attrs - Object of attributes
   * @returns
   */
  function parseAttrs(
    unparsedAttrs?: FormKitSchemaAttributes | FormKitSchemaAttributesCondition,
    bindExp?: string,
    _default = {}
  ): () => FormKitSchemaAttributes {
    const explicitAttrs = new Set(Object.keys(unparsedAttrs || {}))
    const boundAttrs = bindExp ? provider(compile(bindExp)) : () => ({})
    const staticAttrs: FormKitSchemaAttributes = {}
    const setters: Array<(obj: Record<string, any>) => void> = [
      (attrs) => {
        const bound: Record<string, any> = boundAttrs()
        for (const attr in bound) {
          if (!explicitAttrs.has(attr)) {
            attrs[attr] = bound[attr]
          }
        }
      },
    ]
    if (unparsedAttrs) {
      if (isConditional(unparsedAttrs)) {
        // This is a root conditional object that must produce an object of
        // attributes.
        const condition = parseConditionAttr(
          unparsedAttrs,
          _default
        ) as () => FormKitSchemaAttributes
        return condition
      }
      // Some attributes are explicitly bound, we need to parse those ones
      // using the compiler and create a dynamic "setter".
      for (let attr in unparsedAttrs) {
        const value = unparsedAttrs[attr]
        let getValue: () => any
        const isStr = typeof value === 'string'

        if (attr.startsWith(raw)) {
          // attributes prefixed with __raw__ should not be parsed
          attr = attr.substring(7)
          getValue = () => value
        } else if (
          isStr &&
          value.startsWith('$') &&
          value.length > 1 &&
          !(value.startsWith('$reset') && isClassProp.test(attr))
        ) {
          // Most attribute values starting with $ should be compiled
          // -class attributes starting with `$reset` should not be compiled
          getValue = provider(compile(value))
        } else if (typeof value === 'object' && isConditional(value)) {
          // Conditional attrs require further processing
          getValue = parseConditionAttr(value, undefined)
        } else if (typeof value === 'object' && isPojo(value)) {
          // Sub-parse pojos
          getValue = parseAttrs(value)
        } else {
          // In all other cases, the value is static
          getValue = () => value
          staticAttrs[attr] = value
        }
        setters.push((attrs) => {
          attrs[attr] = getValue()
        })
      }
    }
    return () => {
      const attrs = {}
      setters.forEach((setter) => setter(attrs))
      return attrs
    }
  }

  /**
   * Given a single schema node, parse it and extract the value.
   * @param data - A state object provided to each node
   * @param node - The schema node being parsed
   * @returns
   */
  function parseNode(
    library: FormKitComponentLibrary,
    _node: FormKitSchemaNode
  ): RenderContent {
    let element: RenderContent[1] = null
    let attrs: () => FormKitSchemaAttributes = () => null
    let condition: false | (() => boolean | number | string) = false
    let children: RenderContent[3] = null
    let alternate: RenderContent[4] = null
    let iterator: RenderContent[5] = null
    let resolve = false
    const node = sugar(_node)
    if (isDOM(node)) {
      // This is an actual HTML DOM element
      element = node.$el
      attrs =
        node.$el !== 'text' ? parseAttrs(node.attrs, node.bind) : () => null
    } else if (isComponent(node)) {
      // This is a Vue Component
      if (typeof node.$cmp === 'string') {
        if (has(library, node.$cmp)) {
          element = library[node.$cmp]
        } else {
          element = node.$cmp
          resolve = true
        }
      } else {
        // in this case it must be an actual component
        element = node.$cmp
      }
      attrs = parseAttrs(node.props, node.bind)
    } else if (isConditional(node)) {
      // This is an if/then schema statement
      ;[condition, children, alternate] = parseCondition(library, node)
    }

    // This is the same as a "v-if" statement — not an if/else statement
    if (!isConditional(node) && 'if' in node) {
      condition = provider(compile(node.if as string))
    } else if (!isConditional(node) && element === null) {
      // In this odd case our element is actually a partial and
      // we only want to render the children.
      condition = () => true
    }

    // Compile children down to a function
    if ('children' in node && node.children) {
      if (typeof node.children === 'string') {
        // We are dealing with a raw string value
        if (node.children.startsWith('$slots.')) {
          // this is a lone text node, turn it into a slot
          element = element === 'text' ? 'slot' : element
          children = provider(compile(node.children))
        } else if (node.children.startsWith('$') && node.children.length > 1) {
          const value = provider(compile(node.children))
          children = () => String(value())
        } else {
          children = () => String(node.children)
        }
      } else if (Array.isArray(node.children)) {
        // We are dealing with node sub-children
        children = createElements(library, node.children)
      } else {
        // This is a conditional if/else clause
        const [childCondition, c, a] = parseCondition(library, node.children)
        children = (iterationData?: Record<string, unknown>) =>
          childCondition && childCondition()
            ? c && c(iterationData)
            : a && a(iterationData)
      }
    }

    if (isComponent(node)) {
      if (children) {
        // Children of components need to be provided as an object of slots
        // so we provide an object with the default slot provided as children.
        // We also create a new scope for this default slot, and then on each
        // render pass the scoped slot props to the scope.
        const produceChildren = children
        children = (iterationData?: Record<string, unknown>) => {
          return {
            default(
              slotData?: Record<string, any>,
              key?: symbol
            ): RenderableList {
              // We need to switch the current instance key back to the one that
              // originally called this component's render function.
              const currentKey = instanceKey
              if (key) instanceKey = key
              if (slotData) instanceScopes.get(instanceKey)?.unshift(slotData)
              if (iterationData)
                instanceScopes.get(instanceKey)?.unshift(iterationData)
              const c = produceChildren(iterationData)
              // Ensure our instance key never changed during runtime
              if (slotData) instanceScopes.get(instanceKey)?.shift()
              if (iterationData) instanceScopes.get(instanceKey)?.shift()
              instanceKey = currentKey
              return c as RenderableList
            },
          }
        }
        children.slot = true
      } else {
        // If we dont have any children, we still need to provide an object
        // instead of an empty array (which raises a warning in vue)
        children = () => ({})
      }
    }

    // Compile the for loop down
    if ('for' in node && node.for) {
      const values = node.for.length === 3 ? node.for[2] : node.for[1]
      const getValues =
        typeof values === 'string' && values.startsWith('$')
          ? provider(compile(values))
          : () => values
      iterator = [
        getValues,
        node.for[0],
        node.for.length === 3 ? String(node.for[1]) : null,
      ]
    }
    return [condition, element, attrs, children, alternate, iterator, resolve]
  }

  /**
   * Given a particular function that produces children, ensure that the second
   * argument of all these slots is the original instance key being used to
   * render the slots.
   * @param children - The children() function that will produce slots
   */
  function createSlots(
    children: RenderChildren,
    iterationData?: Record<string, unknown>
  ): RenderableSlots | null {
    const slots = children(iterationData) as RenderableSlots
    const currentKey = instanceKey
    return Object.keys(slots).reduce((allSlots, slotName) => {
      const slotFn = slots && slots[slotName]
      allSlots[slotName] = (data?: Record<string, any>) => {
        return (slotFn && slotFn(data, currentKey)) || null
      }
      return allSlots
    }, {} as RenderableSlots)
  }

  /**
   * Creates an element
   * @param data - The context data available to the node
   * @param node - The schema node to render
   * @returns
   */
  function createElement(
    library: FormKitComponentLibrary,
    node: FormKitSchemaNode
  ): RenderNodes {
    // Parses the schema node into pertinent parts
    const [condition, element, attrs, children, alternate, iterator, resolve] =
      parseNode(library, node)
    // This is a sub-render function (called within a render function). It must
    // only use pre-compiled features, and be organized in the most efficient
    // manner possible.
    let createNodes: RenderNodes = ((
      iterationData?: Record<string, unknown>
    ) => {
      if (condition && element === null && children) {
        // Handle conditional if/then statements
        return condition()
          ? children(iterationData)
          : alternate && alternate(iterationData)
      }

      if (element && (!condition || condition())) {
        // handle text nodes
        if (element === 'text' && children) {
          return createTextVNode(String(children()))
        }
        // Handle lone slots
        if (element === 'slot' && children) return children(iterationData)
        // Handle resolving components
        const el = resolve ? resolveComponent(element as string) : element
        // If we are rendering slots as children, ensure their instanceKey is properly added
        const slots: RenderableSlots | null = children?.slot
          ? createSlots(children, iterationData)
          : null
        // Handle dom elements and components
        return h(
          el,
          attrs(),
          (slots || (children ? children(iterationData) : [])) as Renderable[]
        )
      }

      return typeof alternate === 'function'
        ? alternate(iterationData)
        : alternate
    }) as RenderNodes

    if (iterator) {
      const repeatedNode = createNodes
      const [getValues, valueName, keyName] = iterator
      createNodes = (() => {
        const _v = getValues()
        const values = !isNaN(_v as number)
          ? Array(Number(_v))
              .fill(0)
              .map((_, i) => i)
          : _v
        const fragment = []
        if (typeof values !== 'object') return null
        const instanceScope = instanceScopes.get(instanceKey) || []
        for (const key in values) {
          const iterationData: Record<string, unknown> = Object.defineProperty(
            {
              ...instanceScope.reduce(
                (
                  previousIterationData: Record<string, undefined>,
                  scopedData: Record<string, undefined>
                ) => {
                  if (previousIterationData.__idata) {
                    return { ...previousIterationData, ...scopedData }
                  }
                  return scopedData
                },
                {} as Record<string, undefined>
              ),
              [valueName]: values[key],
              ...(keyName !== null ? { [keyName]: key } : {}),
            },
            '__idata',
            { enumerable: false, value: true }
          )
          instanceScope.unshift(iterationData)
          fragment.push(repeatedNode.bind(null, iterationData)())
          instanceScope.shift()
        }
        return fragment
      }) as RenderNodes
    }
    return createNodes as RenderNodes
  }

  /**
   * Given a schema, parse it and return the resulting renderable nodes.
   * @param data - The schema context object
   * @param library - The available components
   * @param node - The node to parse
   * @returns
   */
  function createElements(
    library: FormKitComponentLibrary,
    schema: FormKitSchemaNode | FormKitSchemaNode[]
  ): RenderChildren {
    if (Array.isArray(schema)) {
      const els = schema.map(createElement.bind(null, library))
      return (iterationData?: Record<string, unknown>) =>
        els.map((element) => element(iterationData))
    }
    // Single node to render
    const element = createElement(library, schema)
    return (iterationData?: Record<string, unknown>) => element(iterationData)
  }

  /**
   * Data providers produced as a result of the compiler.
   */
  const providers: ProviderRegistry = []

  /**
   * Append the requisite compiler provider and return the compiled function.
   * @param compiled - A compiled function
   * @returns
   */
  function provider(
    compiled: FormKitCompilerOutput,
    hints: Record<string, boolean> = {}
  ) {
    const compiledFns: Record<symbol, FormKitCompilerOutput> = {}
    providers.push((callback: SchemaProviderCallback, key: symbol) => {
      compiledFns[key] = compiled.provide((tokens) => callback(tokens, hints))
    })
    return () => compiledFns[instanceKey]()
  }

  /**
   * Creates a new instance of a given schema — this either comes from a
   * memoized copy of the parsed schema or a freshly parsed version. An symbol
   * instance key, and dataProvider functions are passed in.
   * @param providerCallback - A function that is called for each required provider
   * @param key - a symbol representing the current instance
   */
  return function createInstance(
    providerCallback: SchemaProviderCallback,
    key
  ) {
    const memoKey = JSON.stringify(schema)
    const [render, compiledProviders] = has(memo, memoKey)
      ? memo[memoKey]
      : [createElements(library, schema), providers]
    memo[memoKey] = [render, compiledProviders]
    compiledProviders.forEach((compiledProvider) => {
      compiledProvider(providerCallback, key)
    })
    return () => {
      instanceKey = key
      return render()
    }
  }
}