function streamReplace()

in bindings/akamai/src/index.ts [38:89]

• 14 lines of code
• 1 McCabe index (conditional complexity)

function streamReplace(
  inputStream: ReadableStream<Uint8Array>,
  targetStr: string,
  replacementStr: string,
): ReadableStream<Uint8Array> {
  let buffer = "";
  const decoder = new TextDecoder("utf-8");
  const encoder = new TextEncoder();
  const inputReader = inputStream.getReader();
  let found = false; // Flag to track if replacement has been made.

  const outputStream = new ReadableStream<Uint8Array>({
    start() {
      buffer = "";
      found = false;
    },
    async pull(controller) {
      const { value: chunk, done: readerDone } = await inputReader.read();

      if (chunk) {
        buffer += decoder.decode(chunk);
      }

      if (!found) {
        // Only perform replacement if not already found.
        let targetIndex = buffer.indexOf(targetStr);
        if (targetIndex !== -1) {
          const beforeTarget = buffer.slice(0, targetIndex);
          const afterTarget = buffer.slice(targetIndex + targetStr.length);
          controller.enqueue(encoder.encode(beforeTarget + replacementStr));
          buffer = afterTarget;
          targetIndex = -1;
          found = true;
        }
      }

      if (readerDone) {
        controller.enqueue(encoder.encode(buffer));
        controller.close();
      } else if (buffer.length > targetStr.length && !found) {
        const safeChunk = buffer.slice(0, buffer.length - targetStr.length);
        controller.enqueue(encoder.encode(safeChunk));
        buffer = buffer.slice(buffer.length - targetStr.length);
      }
    },
    cancel() {
      inputReader.cancel();
    },
  });

  return outputStream;
}