describeNativeComponentFrame() — react Function Reference

Source Code

packages/react-devtools-shared/src/backend/shared/DevToolsComponentStackFrame.js lines 54–135

export function describeNativeComponentFrame(
  fn: Function,
  construct: boolean,
  currentDispatcherRef: CurrentDispatcherRef,
): string {
  // If something asked for a stack inside a fake render, it should get ignored.
  if (!fn || reentry) {
    return '';
  }

  if (__DEV__) {
    const frame = componentFrameCache.get(fn);
    if (frame !== undefined) {
      return frame;
    }
  }

  const previousPrepareStackTrace = Error.prepareStackTrace;
  // $FlowFixMe[incompatible-type] It does accept undefined.
  Error.prepareStackTrace = undefined;

  reentry = true;

  // Override the dispatcher so effects scheduled by this shallow render are thrown away.
  //
  // Note that unlike the code this was forked from (in ReactComponentStackFrame)
  // DevTools should override the dispatcher even when DevTools is compiled in production mode,
  // because the app itself may be in development mode and log errors/warnings.
  const previousDispatcher = currentDispatcherRef.H;
  currentDispatcherRef.H = null;
  disableLogs();
  try {
    // NOTE: keep in sync with the implementation in ReactComponentStackFrame

    /**
     * Finding a common stack frame between sample and control errors can be
     * tricky given the different types and levels of stack trace truncation from
     * different JS VMs. So instead we'll attempt to control what that common
     * frame should be through this object method:
     * Having both the sample and control errors be in the function under the
     * `DescribeNativeComponentFrameRoot` property, + setting the `name` and
     * `displayName` properties of the function ensures that a stack
     * frame exists that has the method name `DescribeNativeComponentFrameRoot` in
     * it for both control and sample stacks.
     */
    const RunInRootFrame = {
      DetermineComponentFrameRoot(): [?string, ?string] {
        let control;
        try {
          // This should throw.
          if (construct) {
            // Something should be setting the props in the constructor.
            const Fake = function () {
              throw Error();
            };
            // $FlowFixMe[prop-missing]
            Object.defineProperty(Fake.prototype, 'props', {
              set: function () {
                // We use a throwing setter instead of frozen or non-writable props
                // because that won't throw in a non-strict mode function.
                throw Error();
              },
            });
            if (typeof Reflect === 'object' && Reflect.construct) {
              // We construct a different control for this case to include any extra
              // frames added by the construct call.
              try {
                Reflect.construct(Fake, []);
              } catch (x) {
                control = x;
              }
              Reflect.construct(fn, [], Fake);
            } else {
              try {
                Fake.call();
              } catch (x) {
                control = x;
              }
              // $FlowFixMe[prop-missing] found when upgrading Flow
              fn.call(Fake.prototype);
            }