49 lines
1.1 KiB
TypeScript
49 lines
1.1 KiB
TypeScript
export type FixedWindowRateLimiter = {
|
|
consume: () => {
|
|
allowed: boolean;
|
|
retryAfterMs: number;
|
|
remaining: number;
|
|
};
|
|
reset: () => void;
|
|
};
|
|
|
|
export function createFixedWindowRateLimiter(params: {
|
|
maxRequests: number;
|
|
windowMs: number;
|
|
now?: () => number;
|
|
}): FixedWindowRateLimiter {
|
|
const maxRequests = Math.max(1, Math.floor(params.maxRequests));
|
|
const windowMs = Math.max(1, Math.floor(params.windowMs));
|
|
const now = params.now ?? Date.now;
|
|
|
|
let count = 0;
|
|
let windowStartMs = 0;
|
|
|
|
return {
|
|
consume() {
|
|
const nowMs = now();
|
|
if (nowMs - windowStartMs >= windowMs) {
|
|
windowStartMs = nowMs;
|
|
count = 0;
|
|
}
|
|
if (count >= maxRequests) {
|
|
return {
|
|
allowed: false,
|
|
retryAfterMs: Math.max(0, windowStartMs + windowMs - nowMs),
|
|
remaining: 0,
|
|
};
|
|
}
|
|
count += 1;
|
|
return {
|
|
allowed: true,
|
|
retryAfterMs: 0,
|
|
remaining: Math.max(0, maxRequests - count),
|
|
};
|
|
},
|
|
reset() {
|
|
count = 0;
|
|
windowStartMs = 0;
|
|
},
|
|
};
|
|
}
|