recursivelyTraverseItems() — react Function Reference

Source Code

compiler/packages/babel-plugin-react-compiler/src/HIR/AssertValidBlockNesting.ts lines 113–152

export function recursivelyTraverseItems<T, TContext>(
  items: Array<T>,
  getRange: (val: T) => MutableRange,
  context: TContext,
  enter: (val: T, context: TContext) => void,
  exit: (val: T, context: TContext) => void,
): void {
  items.sort((a, b) => rangePreOrderComparator(getRange(a), getRange(b)));
  let activeItems: Array<T> = [];
  const ranges = items.map(getRange);
  for (let i = 0; i < items.length; i++) {
    const curr = items[i];
    const currRange = ranges[i];
    for (let i = activeItems.length - 1; i >= 0; i--) {
      const maybeParent = activeItems[i];
      const maybeParentRange = getRange(maybeParent);
      const disjoint = currRange.start >= maybeParentRange.end;
      const nested = currRange.end <= maybeParentRange.end;
      CompilerError.invariant(disjoint || nested, {
        reason: 'Invalid nesting in program blocks or scopes',
        description: `Items overlap but are not nested: ${maybeParentRange.start}:${maybeParentRange.end}(${currRange.start}:${currRange.end})`,
        loc: GeneratedSource,
      });
      if (disjoint) {
        exit(maybeParent, context);
        activeItems.length = i;
      } else {
        break;
      }
    }
    enter(curr, context);
    activeItems.push(curr);
  }

  let curr = activeItems.pop();
  while (curr != null) {
    exit(curr, context);
    curr = activeItems.pop();
  }
}