addDependency() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/HIR/DeriveMinimalDependenciesHIR.ts lines 104–181

  addDependency(dep: ReactiveScopeDependency): void {
    const {identifier, reactive, path} = dep;
    let depCursor = ReactiveScopeDependencyTreeHIR.#getOrCreateRoot(
      identifier,
      reactive,
      this.#deps,
      PropertyAccessType.UnconditionalAccess,
    );
    /**
     * hoistableCursor is null if depCursor is not an object we can hoist
     * property reads from otherwise, it represents the same node in the
     * hoistable / cfg-informed tree
     */
    let hoistableCursor: HoistableNode | undefined =
      this.#hoistableObjects.get(identifier);

    // All properties read 'on the way' to a dependency are marked as 'access'
    for (const entry of path) {
      let nextHoistableCursor: HoistableNode | undefined;
      let nextDepCursor: DependencyNode;
      if (entry.optional) {
        /**
         * No need to check the access type since we can match both optional or non-optionals
         * in the hoistable
         *  e.g. a?.b<rest> is hoistable if a.b<rest> is hoistable
         */
        if (hoistableCursor != null) {
          nextHoistableCursor = hoistableCursor?.properties.get(entry.property);
        }

        let accessType;
        if (
          hoistableCursor != null &&
          hoistableCursor.accessType === 'NonNull'
        ) {
          /**
           * For an optional chain dep `a?.b`: if the hoistable tree only
           * contains `a`, we can keep either `a?.b` or 'a.b' as a dependency.
           * (note that we currently do the latter for perf)
           */
          accessType = PropertyAccessType.UnconditionalAccess;
        } else {
          /**
           * Given that it's safe to evaluate `depCursor` and optional load
           * never throws, it's also safe to evaluate `depCursor?.entry`
           */
          accessType = PropertyAccessType.OptionalAccess;
        }
        nextDepCursor = makeOrMergeProperty(
          depCursor,
          entry.property,
          accessType,
        );
      } else if (
        hoistableCursor != null &&
        hoistableCursor.accessType === 'NonNull'
      ) {
        nextHoistableCursor = hoistableCursor.properties.get(entry.property);
        nextDepCursor = makeOrMergeProperty(
          depCursor,
          entry.property,
          PropertyAccessType.UnconditionalAccess,
        );
      } else {
        /**
         * Break to truncate the dependency on its first non-optional entry that PropertyLoads are not hoistable from
         */
        break;
      }
      depCursor = nextDepCursor;
      hoistableCursor = nextHoistableCursor;
    }
    // mark the final node as a dependency
    depCursor.accessType = merge(
      depCursor.accessType,
      PropertyAccessType.OptionalDependency,
    );
  }