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@tenets/invariant

v0.6.0

Published

6 days ago

Assertion primitive for impossible internal states, throwing InvariantError — the API surface the tenets ruleset requires (Rule 7.6).

Downloads

496

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@tenets/invariant

invariant(condition, message) for states that are impossible when the code is correct, throwing InvariantError. Never catch an invariant failure to recover (Rule 2.2) — it marks a programmer bug, not a recoverable condition.

The tenets ruleset's TypeScript profile fixes these API names (Rule 7.6); your project guide records where the package lives.

Credit

Descends from Facebook's classic invariant (of fbjs/React lineage) and Alex Reardon's tiny-invariant, keeping the familiar %s message formatting. This package exists for what production assertion handling needs beyond a bare throw:

A typed failure class — InvariantError with stable code, optional docsUrl, structured details, and cause, so crash reporting can group and link failures.
Configurable production stripping — createInvariant({ mode: 'production' }) strips diagnostic messages (which may embed sensitive values) while the check itself always runs; development mode requires messages so diagnostics cannot silently go missing.
Zero dependencies.