> For the complete documentation index, see [llms.txt](https://wong-coupon.gitbook.io/flutter/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wong-coupon.gitbook.io/flutter/my-reactjs/financial-javascript.md).

# Financial JavaScript

Precision, units, and rounding; idempotency, duplicate-submit prevention, and expiry.

Precision, units, and rounding; idempotency, duplicate-submit prevention, and expiry.

## Articles

* [Precise Financial Math in TypeScript](/flutter/my-reactjs/financial-javascript/precise-financial-math-typescript.md) — Keep decimals, units, scale, and rounding policy consistent from ingress to the wire boundary without treating client estimates as accounting truth.
* [Money and Rate Unit Boundaries](/flutter/my-reactjs/financial-javascript/money-rate-unit-boundaries.md) — Separate API, form, and request units with named adapters, keeping amounts distinct from prices and ratios from percentages.
* [Rounding at the Right Boundary](/flutter/my-reactjs/financial-javascript/rounding-truncation-boundaries.md) — Define rounding stage, mode, and ownership; keep previews separate from request totals.
* [Request IDs and Idempotency](/flutter/my-reactjs/financial-javascript/request-id-idempotency.md) — Preserve intent identity across attempts and test replay after response loss following a commit.
* [Preventing Double Submits in React](/flutter/my-reactjs/financial-javascript/prevent-double-submit-react.md) — Hold submission admission across validation, confirmation, and the request without confusing loading with operation ownership.
* [Countdowns and Expiry in React](/flutter/my-reactjs/financial-javascript/countdown-expiry-react.md) — Bind clock readings to the correct deadline, separate uncertainty from expiry, and verify cleanup with real React.
* [Precise Number Display in React](/flutter/my-reactjs/financial-javascript/precise-number-display-react.md) — Preserve exact decimals through text, comparison, and locale; do not turn zero into unavailable.

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