import { type WidthKey } from "./tokens.js";
/**
 * One axis of a component's semantic props: the members in precedence order (each
 * beats every member after it), what each resolves to, and the fallback when none is
 * set.
 */
export interface Axis<M extends string, V = M, D = null> {
    /** The members, highest precedence first. */
    readonly members: readonly M[];
    /** What each member resolves to. */
    readonly values: Readonly<Record<M, V>>;
    /** What the axis resolves to when the props set no member. */
    readonly fallback: D;
}
/** The members of an axis. */
export type MemberOf<A> = A extends Axis<infer M, unknown, unknown> ? M : never;
/** Everything an axis can resolve to: a member's value or the fallback. */
export type ResolvedOf<A> = A extends Axis<string, infer V, infer D> ? V | D : never;
/** The keys of `P` whose values are booleans: the only props an axis may name. */
export type BooleanProps<P> = {
    [K in keyof P]-?: [NonNullable<P[K]>] extends [never] ? never : [NonNullable<P[K]>] extends [boolean] ? K : never;
}[keyof P] & string;
/** An axis whose members resolve to themselves, with no fallback (`null`). */
export declare function axis<const M extends string>(members: readonly M[]): Axis<M, M, null>;
/** An axis whose members resolve to themselves, and `fallback` when none is set. */
export declare function axis<const M extends string, const D>(members: readonly M[], fallback: D): Axis<M, M, D>;
/** An axis whose members resolve to their values in `values`, declared in precedence order, with no fallback (`null`). */
export declare function axis<const R extends Record<string, unknown>>(values: R): Axis<keyof R & string, R[keyof R], null>;
/** An axis whose members resolve to their values in `values`, declared in precedence order, and `fallback` when none is set. */
export declare function axis<const R extends Record<string, unknown>, const D>(values: R, fallback: D): Axis<keyof R & string, R[keyof R], D>;
/**
 * Resolve an axis against a component's props: the value of the highest-precedence
 * member the props set (a member counts as set when its prop is truthy, as an `if`
 * reads it), or the axis's fallback when they set none. Every member must be a
 * boolean prop of the props type, so a table that names a prop the component does
 * not declare fails to compile where the component resolves it.
 */
export declare function pick<P extends object, M extends BooleanProps<P>, V, D>(a: Axis<M, V, D>, p: P): V | D;
/**
 * The measure axis (`MeasureProps` in sizing.ts): the steps of the width scale,
 * narrowest first, so the narrowest step passed wins and a stray wider step never
 * widens a deliberate narrow one. The members come from `widths` itself, in its
 * declaration order; no step is listed twice.
 */
export declare const MEASURE: Axis<WidthKey, WidthKey, null>;
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