The original title is: "await doesn't mean 'meanwhile': the bug every JavaScript engineer writes in Python"

Short summary

JavaScript async functions execute eagerly—work starts immediately upon calling—while Python async def creates lazy coroutines that defer execution until awaited. This means the JavaScript pattern of 'call early, await late' for concurrent I/O translates to pure sequential execution in Python unless coroutines are wrapped in asyncio.create_task(). Use asyncio.gather() or TaskGroup to achieve true parallel execution.

• •JavaScript async functions are eager (start on call); Python coroutines are lazy (start on await)
• •JavaScript's 'call early, await late' concurrency pattern fails in Python without asyncio.create_task()
• •Use asyncio.gather() or TaskGroup for true parallel execution in Python

Generated with AI, which can make mistakes.