Type Alias FieldValidator<T>

Type Declaration

• • (
        value: unknown,
        field: string,
        context: CommandContext,
        preloaded: T,
    ): string | undefined

  • Parameters

    • value: unknown
    • field: string
    • context: CommandContext
    • preloaded: T

    Returns string | undefined

• Optionalpreload?: (value: unknown, field: string, context: CommandContext) => Promise<T>

  Optional async preload. The dispatcher awaits each preload AFTER MQL resolution but BEFORE the sync validator phase runs (see CommandApi.preloadValidatorDeps), so the sync body's data is ready before it runs.

  The preload's resolved value is passed back to the sync body as its fourth argument (preloaded). For validators whose preload just warms a singleton cache (the original use-case — e.g., a requiresAnimateTarget validator preloading a species clade so the sync findByTemplatePath hits warm), return void and the sync body ignores the extra arg. For validators whose sync decision is itself async (e.g., the access checks), return the decision directly and the sync body reads it from preloaded.

  Signature mirrors the sync body — (value, field, context). Field validators that want per-bound-target deps inspect the resolved Stuff and preload accordingly. Validators that only need giver-side deps ignore value / field and read context.commandGiver.

  // Cache-warming preload (legacy shape — returns void):
  const v: FieldValidator = (value, field, ctx) => { ... };
  v.preload = async (value, field, ctx) => {
    await StuffApi.singleton(somePathFromTarget(value));
  };
  
  // Decision-returning preload:
  const v: FieldValidator<boolean> = (_v, _f, _ctx, allowed) =>
    allowed ? undefined : 'denied';
  v.preload = async (_v, _f, ctx) => AccessApi.can(ctx.commandGiver, 'x', null);
  Copy

  Omit on validators that only check mixin presence or call sync-pure helpers.