Function rateLimited

rateLimited<ArgsType extends unknown[], T>(
fn: (...args: ArgsType) => Promise<T>,
duration_ms: number | (() => number),
): RateLimitedFunction<ArgsType, T>
Wraps an asynchronous function so that it is executed at most once every duration_ms milliseconds. Additional calls are queued and processed sequentially following a strict FIFO (first-come first-served) order.

This is useful when throttling API calls or expensive operations.
Type Parameters
- ArgsType extends unknown[]
  Parameter tuple type of the wrapped function.
- T
  Resolved return type of the wrapped function.
Parameters
- fn: (...args: ArgsType) => Promise<T>
  The asynchronous function to rate-limit.
- duration_ms: number | (() => number)
  Either a fixed number of milliseconds, or a function that returns the delay dynamically at each scheduling point.
Returns RateLimitedFunction<ArgsType, T>
A RateLimitedFunction instance that enforces the rate limit.
Example
```
const limitedFetch = rateLimited(fetchJson, 500);

await limitedFetch("/endpoint"); // executes immediately
await limitedFetch("/endpoint"); // queued and executed ≥500ms later
console.log(limitedFetch.wait_count); // number of queued calls
```
- Defined in function/rate-limit.ts:68