verdict-rules/dist/rule.d.ts

A small, zero-dependency, async-native rule-evaluation engine. Compose conditions into one explainable pass/fail verdict, with sequential evaluation and real short-circuiting as a guarantee.

import type { RuleResult } from "./result.js";
/**
 * The contract every rule satisfies.
 *
 * A plain `interface` — structural typing: any object of the right shape
 * is a `Rule`. No `implements` clause, no base class, no registration.
 *
 * `Rule<TContext>` is generic over the context it reads from, with no
 * default type parameter. Dict-context is `Rule<Context>`, written out
 * every time.
 *
 * ```ts
 * const overEighteen: Rule<Context> = {
 *   name: "over_18",
 *   async evaluate(ctx) {
 *     return { ruleName: "over_18", passed: (ctx.age as number) >= 18 };
 *   },
 * };
 * ```
 */
export interface Rule<TContext> {
    /**
     * Unique identifier for this rule, used for engine lookups and to attribute
     * a result back to its source.
     */
    readonly name: string;
    /** Optional group label. Rules sharing one can be run together. */
    readonly group?: string | undefined;
    /** Evaluate this rule against `context`. */
    evaluate(context: TContext): Promise<RuleResult>;
}
/** Signature of the predicate {@link FunctionRule} wraps. */
export type RulePredicate<TContext> = (context: TContext) => Promise<RuleResult>;
/**
 * Wraps a plain async predicate as a {@link Rule}.
 *
 * `TContext` is inferred from the wrapped predicate's own parameter type.
 */
export declare class FunctionRule<TContext> implements Rule<TContext> {
    #private;
    readonly name: string;
    readonly group: string | undefined;
    constructor(name: string, predicate: RulePredicate<TContext>, group?: string);
    /** Runs the wrapped predicate and returns whatever it returns, unchanged. */
    evaluate(context: TContext): Promise<RuleResult>;
}
/**
 * Composite that passes only if every sub-rule passes.
 *
 * Short-circuits on the first failing sub-rule.
 *
 * An empty list passes vacuously.
 *
 * Every sub-rule must share the exact same `TContext`.
 */
export declare class AndRule<TContext> implements Rule<TContext> {
    #private;
    readonly name: string;
    readonly group: string | undefined;
    constructor(name: string, rules: readonly Rule<TContext>[], group?: string);
    evaluate(context: TContext): Promise<RuleResult>;
}
/**
 * Composite that passes as soon as any sub-rule passes.
 *
 * Short-circuits on the first passing sub-rule.
 *
 * An empty list fails vacuously. The same same-`TContext` requirement
 * across sub-rules applies here too.
 */
export declare class OrRule<TContext> implements Rule<TContext> {
    #private;
    readonly name: string;
    readonly group: string | undefined;
    constructor(name: string, rules: readonly Rule<TContext>[], group?: string);
    evaluate(context: TContext): Promise<RuleResult>;
}