react源码分析

ReactMount.render -> ReactMount._renderSubtreeIntoContainer

-> ReactMount._renderNewRootComponent -> ReactMount.batchedMountComponentIntoNode

-> ReactReconciler.mountComponent -> ReactDomComponent.mountComponent

-> ReactDomComponent._createContentMarkup ->ReactMultiChild.mountChildren

->  ReactMount._mountImageIntoNode -> ReactMount.setInnerHTML

ReactMount._mountImageIntoNode负责将virtualdom实际mount到dom上，

先是用ReactMarkupChecksum.canReuseMarkup检查是不是可以复用的markup

/**
 * Mounting is the process of initializing a React component by creating its
 * representative DOM elements and inserting them into a supplied `container`.
 * Any prior content inside `container` is destroyed in the process.
 *
 *   ReactMount.render(
 *     component,
 *     document.getElementById('container')
 *   );
 *
 *   <div id="container">                   <-- Supplied `container`.
 *     <div data-reactid=".3">              <-- Rendered reactRoot of React
 *       // ...                                 component.
 *     </div>
 *   </div>
 *
 * Inside of `container`, the first element rendered is the "reactRoot".
 */

    if (transaction.useCreateElement) {
      while (container.lastChild) {
        container.removeChild(container.lastChild);
      }
      container.appendChild(markup);
    } else {
      setInnerHTML(container, markup);
    }

Transaction

/*
 * Use cases:
 * - Preserving the input selection ranges before/after reconciliation.
 *   Restoring selection even in the event of an unexpected error.
 * - Deactivating events while rearranging the DOM, preventing blurs/focuses,
 *   while guaranteeing that afterwards, the event system is reactivated.
 * - Flushing a queue of collected DOM mutations to the main UI thread after a
 *   reconciliation takes place in a worker thread.
 * - Invoking any collected `componentDidUpdate` callbacks after rendering new
 *   content.
 * - (Future use case): Wrapping particular flushes of the `ReactWorker` queue
 *   to preserve the `scrollTop` (an automatic scroll aware DOM).
 * - (Future use case): Layout calculations before and after DOM updates.
 *
 * Transactional plugin API:
 * - A module that has an `initialize` method that returns any precomputation.
 * - and a `close` method that accepts the precomputation. `close` is invoked
 *   when the wrapped process is completed, or has failed.
 *
 * @param {Array<TransactionalWrapper>} transactionWrapper Wrapper modules
 * that implement `initialize` and `close`.
 * @return {Transaction} Single transaction for reuse in thread.
 *
 * @class Transaction
 */