TypeScript nerv-shared.isValidElement函数代码示例

function normalizeChildren (children) {
  if (isArray(children)) {
    return children.filter(isValidElement).map(updateReactComponent)
  } else {
    return isValidElement(children) ? [updateReactComponent(children)] : []
  }
}

function h (type: string, props: Props, children?: VirtualChildren) {
  let childNodes
  if (props.children) {
    if (!children) {
      children = props.children
    }
    delete props.children
  }
  if (isArray(children)) {
    childNodes = []
    addChildren(childNodes, children as any, type)
  } else if (isString(children) || isNumber(children)) {
    children = createVText(String(children))
  } else if (!isValidElement(children)) {
    children = EMPTY_CHILDREN
  }
  return createVNode(
    type,
    props,
    childNodes !== undefined ? childNodes : children,
    props.key,
    props.namespace,
    props.owner,
    props.ref
  ) as VNode
}

export function unmountComponentAtNode (dom) {
  const component = dom._component
  if (isValidElement(component)) {
    unmount(component, dom)
    delete dom._component
    return true
  }
  return false
}

function addChildren (
  childNodes: VirtualNode[],
  children: VirtualNode | VirtualNode[],
  type: string
) {
  if (isString(children) || isNumber(children)) {
    childNodes.push(createVText(String(children)))
  } else if (isValidElement(children)) {
    childNodes.push(children)
  } else if (isArray(children)) {
    for (let i = 0; i < children.length; i++) {
      addChildren(childNodes, children[i], type)
    }
  }
}

function createElement (
  vnode: VirtualNode | VirtualNode[],
  isSvg?: boolean,
  parentContext?,
  parentComponent?
): Element | Text | Comment | DocumentFragment | null {
  let domNode
  if (isValidElement(vnode)) {
    const vtype = vnode.vtype
    if (vtype & (VType.Composite | VType.Stateless)) {
      domNode = (vnode as CompositeComponent).init(parentContext, parentComponent)
      options.afterMount(vnode as CompositeComponent)
    } else if (vtype & VType.Text) {
      domNode = doc.createTextNode((vnode as any).text);
      (vnode as any).dom = domNode
    } else if (vtype & VType.Node) {
      domNode = mountVNode(vnode as any, isSvg, parentContext, parentComponent)
    } else if (vtype & VType.Void) {
      domNode = (vnode as any).dom
    }
  } else if (isString(vnode) || isNumber(vnode)) {
    domNode = doc.createTextNode(vnode as string)
  } else if (isNullOrUndef(vnode) || (vnode as any) === false) {
    domNode = doc.createTextNode('')
  } else if (isArray(vnode)) {
    domNode = doc.createDocumentFragment()
    vnode.forEach((child) => {
      if (!isInvalid(child)) {
        const childNode = createElement(child, isSvg, parentContext, parentComponent)
        if (childNode) {
          domNode.appendChild(childNode)
        }
      }
    })
  } else {
    throw new Error('Unsupported VNode.')
  }
  return domNode
}

export function patchProp (
  domNode: Element,
  prop: string,
  lastValue,
  nextValue,
  lastVnode: VNode | null,
  isSvg?: boolean
) {
  if (lastValue !== nextValue) {
    if (prop === 'className') {
      prop = 'class'
    }
    if (skipProps[prop] === 1) {
      return
    } else if (prop === 'class' && !isSvg) {
      domNode.className = nextValue
    } else if (prop === 'dangerouslySetInnerHTML') {
      const lastHtml = lastValue && lastValue.__html
      const nextHtml = nextValue && nextValue.__html

      if (lastHtml !== nextHtml) {
        if (!isNullOrUndef(nextHtml)) {
          if (
            isValidElement(lastVnode) &&
            lastVnode.children !== EMPTY_CHILDREN
          ) {
            unmountChildren(lastVnode.children)
            lastVnode.children = []
          }
          domNode.innerHTML = nextHtml
        }
      }
    } else if (isAttrAnEvent(prop)) {
      patchEvent(prop, lastValue, nextValue, domNode)
    } else if (prop === 'style') {
      patchStyle(lastValue, nextValue, domNode)
    } else if (
      prop !== 'list' &&
      prop !== 'type' &&
      !isSvg &&
      prop in domNode
    ) {
      setProperty(domNode, prop, nextValue == null ? '' : nextValue)
      if (nextValue == null || nextValue === false) {
        domNode.removeAttribute(prop)
      }
    } else if (isNullOrUndef(nextValue) || nextValue === false) {
      domNode.removeAttribute(prop)
    } else {
      const namespace = SVGPropertyConfig.DOMAttributeNamespaces[prop]
      if (isSvg && namespace) {
        if (nextValue) {
          domNode.setAttributeNS(namespace, prop, nextValue)
        } else {
          const colonPosition = prop.indexOf(':')
          const localName =
            colonPosition > -1 ? prop.substr(colonPosition + 1) : prop
          domNode.removeAttributeNS(namespace, localName)
        }
      } else {
        if (!isFunction(nextValue)) {
          domNode.setAttribute(prop, nextValue)
        }
        // WARNING: Non-event attributes with function values:
        // https://reactjs.org/blog/2017/09/08/dom-attributes-in-react-16.html#changes-in-detail
      }
    }
  }
}