UNPKG

serverless-spy

Version:

CDK-based library for writing elegant integration tests on AWS serverless architecture and an additional web console to monitor events in real time.

32 lines (31 loc) 923 B
export async function headStream(stream, bytes) { let byteLengthCounter = 0; const chunks = []; const reader = stream.getReader(); let isDone = false; while (!isDone) { const { done, value } = await reader.read(); if (value) { chunks.push(value); byteLengthCounter += value?.byteLength ?? 0; } if (byteLengthCounter >= bytes) { break; } isDone = done; } reader.releaseLock(); const collected = new Uint8Array(Math.min(bytes, byteLengthCounter)); let offset = 0; for (const chunk of chunks) { if (chunk.byteLength > collected.byteLength - offset) { collected.set(chunk.subarray(0, collected.byteLength - offset), offset); break; } else { collected.set(chunk, offset); } offset += chunk.length; } return collected; }