Function createArrayIteratorHandler

packages/db/src/proxy.ts:184–229

* Creates a Symbol.iterator handler for arrays that yields proxied elements.

(
  changeTracker: ChangeTracker<T>,
  memoizedCreateChangeProxy: (
    obj: Record<string | symbol, unknown>,
    parent?: {
      tracker: ChangeTracker<Record<string | symbol, unknown>>
      prop: string | symbol
    },
  ) => { proxy: Record<string | symbol, unknown> },
)

 * Creates a Symbol.iterator handler for arrays that yields proxied elements.
 */
function createArrayIteratorHandler<T extends object>(
  changeTracker: ChangeTracker<T>,
  memoizedCreateChangeProxy: (
    obj: Record<string | symbol, unknown>,
    parent?: {
      tracker: ChangeTracker<Record<string | symbol, unknown>>
      prop: string | symbol
    },
  ) => { proxy: Record<string | symbol, unknown> },
): () => Iterator<unknown> {
  return function () {
    const array = changeTracker.copy_ as unknown as Array<unknown>
    let index = 0

    return {
      next() {
        if (index >= array.length) {
          return { done: true, value: undefined }
        }

        const element = array[index]
        let proxiedElement = element

        if (isProxiableObject(element)) {
          const nestedParent = {
            tracker: changeTracker as unknown as ChangeTracker<
              Record<string | symbol, unknown>
            >,
            prop: String(index),
          }
          const { proxy: elementProxy } = memoizedCreateChangeProxy(
            element,
            nestedParent,
          )
          proxiedElement = elementProxy
        }

        index++
        return { done: false, value: proxiedElement }
      },
      [Symbol.iterator]() {
        return this
      },
    }
  }
}

/**
 * Creates a wrapper for methods that modify a collection (array, Map, Set).