KitError taxonomy

One frozen 10-code taxonomy drives every failure path — and the single styled error layout, with copy swapped by code. Every throw in the SDK is a typed KitError, never a bare string.

KitError shape

KitError extends Error with a typed, exhaustive code. The 10 codes live in the frozen KIT_ERROR_CODES tuple, and isKitError is the type guard. All three come from @soropass/core/types (≈182 B gzipped).

import { KitError, KIT_ERROR_CODES, isKitError } from '@soropass/core/types';
import type { KitErrorCode } from '@soropass/core/types';

class KitError extends Error {
  readonly code: KitErrorCode;   // one of KIT_ERROR_CODES
  readonly cause?: unknown;      // the underlying error, when wrapped
}

Guard pattern

import { isKitError } from '@soropass/core/types';

if (isKitError(err)) {
  switch (err.code) {
    case 'USER_CANCELLED': return retry();
    case 'NETWORK_ERROR': return retry();
    // …exhaustive over KIT_ERROR_CODES
  }
}

The 10 codes

From code to styled copy

The headless layer surfaces a screen-agnostic KitErrorCode; the styled layer's error connector maps (screen, code) → a screen-scoped copy key (e.g. create:cancelled, sign:verify) so the same 10 codes read naturally on each screen. One layout, copy swapped by code — see it live on the Sign and Create state galleries.