/**
 * An if-else branch using function composition.
 * @param condition - a constant boolean value or a function that resolves to a boolean
 * @param pass - a function to execute if the condition passes
 * @param fail - a function to execute if the condition fails
 * @returns the result of calling pass if the condition is true, or the result of calling fail if not
 * ```typescript
 * pipe(
 *   5,
 *   ifElse(
 *     num => num > 3,
 *     num => num / 2, // -> 2.5
 *     num => num * 2
 *   )
 * );
 *
 * pipe(
 *   2,
 *   ifElse(
 *     num => num > 3,
 *     num => num / 2,
 *     num => num * 2 // -> 4
 *   )
 * );
 * ```
 */
export declare function ifElse<V, R1, R2 = R1>(condition: ((value: V) => boolean) | boolean, pass: (value: V) => R1, fail: (value: V) => R2): (value: V) => R1 | R2;
/**
 * An if-then branch using function composition
 * @param condition - a constant boolean value or a function that resolves to a boolean
 * @param pass - a function to execute if the condition passes
 * @returns the result of calling pass if the condition is true, or the initial value if not
 * ```typescript
 * pipe(
 *   5,
 *   ifThen(
 *     num => num > 3,
 *     num => num / 2 // -> 2.5
 *   )
 * );
 *
 * pipe(
 *   2,
 *   ifThen(
 *     num => num > 3,
 *     num => num / 2
 *   ) // -> 2
 * );
 * ``
 */
export declare function ifThen<V, R>(condition: ((value: V) => boolean) | boolean, pass: (value: V) => R): (value: V) => R | V;
/**
 * A switch-case expression using function composition.
 * @param conditions - an array of pairs matching a boolean value or a function returning a boolean, to a function to execute if true
 * @returns the result of the function matching the first true condition
 * ```typescript
 * switchCase([
 *   [ () => false, () => 4 ],
 *   [ () => true, () => 3], // -> 3
 *   [ true, () => 2 ]
 * ]);
 * ```
 */
export declare function switchCase<R>(conditions: [(() => boolean) | boolean, () => R][]): R | undefined;