feat: expose rate limit headers via onRateLimitInfo callback#86
Merged
mikeh-lago merged 2 commits intomainfrom May 5, 2026
Merged
feat: expose rate limit headers via onRateLimitInfo callback#86mikeh-lago merged 2 commits intomainfrom
mikeh-lago merged 2 commits intomainfrom
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Surface x-ratelimit-* headers from successful responses so callers can build observability around the rate limit (warn at thresholds, emit metrics) without inspecting internals. - Add RateLimitInfo type with parseRateLimitInfo + rateLimitUsagePct helpers - Add onRateLimitInfo option on RateLimitFetchConfig - Parse and emit headers on every non-429 response in createRateLimitFetch - Ship loggingRateLimitObserver as a zero-config observer (defaults: 80/90/95%) - Callback errors are caught and logged so they cannot break requests - Backward-compatible: callback is optional, default behavior unchanged
vincent-pochet
approved these changes
May 5, 2026
Address review feedback from @vincent-pochet on PR #86: - Honor Request.method when input is a Request and init.method is undefined (a valid fetch signature). Previously this fell through to 'GET' regardless of the actual method on the Request. - Only emit on_rate_limit_info on 2xx responses. Non-429 errors no longer trigger the callback. This matches the comment on the call site, the docstring on the option, and the behavior of the Python, Go, Ruby, and Rust SDKs. - Add tests for the Request input case and for the 5xx no-emit case.
vincent-pochet
approved these changes
May 5, 2026
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Adds an optional
onRateLimitInfocallback onRateLimitFetchConfigso callers can readx-ratelimit-*headers from successful responses. Today the SDK drops them on 2xx, which makes 80/90/95% threshold observability impossible without inspecting internals. The 429 path (viaLagoRateLimitError) is unchanged. Mirrors PRs getlago/lago-python-client#393, getlago/lago-go-client#336, and getlago/lago-ruby-client#347.Notes for review
console.warnso a buggy observer can't break a request.Tests
12 new tests in
tests/rate_limit.test.ts.deno task testpasses (98 tests).deno task buildproduces a clean npm package.