main.ts

import { chain } from './case.js'

export type { Condition, Options, Switch } from './types.js'

/**
 * Functional switch statement. This must be chained with
 * `.case()` statements and end with `.default()`.
 *
 * @example <caption>Basic usage</caption>
 * ```js
 * import switchFunctional from 'switch-functional'
 *
 * const getUserType = (user) =>
 *   switchFunctional(user.type)
 *     .case('dev', 'developer')
 *     .case(['admin', 'owner'], 'administrator')
 *     .default('unknown')
 * ```
 *
 * This is equivalent to:
 *
 * ```js
 * const getUserType = (user) => {
 *   switch (user.type) {
 *     case 'dev': {
 *       return 'developer'
 *     }
 *
 *     case 'admin':
 *
 *     case 'owner': {
 *      return 'administrator'
 *     }
 *
 *     default: {
 *       return 'unknown'
 *     }
 *   }
 * }
 * ```
 *
 * @example <caption>Testing input</caption>
 * ```js
 * const getUserType = (user) =>
 *   switchFunctional(user)
 *     .case(isDeveloper, 'developer')
 *     .case([isAdmin, isOwner], 'admin')
 *     .default('unknown')
 * ```
 *
 * This is equivalent to:
 *
 * ```js
 * const getUserType = (user) => {
 *   if (isDeveloper(user)) {
 *     return 'developer'
 *   }
 *
 *   if (isAdmin(user) || isOwner(user)) {
 *     return 'admin'
 *   }
 *
 *   return 'unknown'
 * }
 * ```
 *
 * @example <caption>Testing properties</caption>
 * ```js
 * const getUserType = (user) =>
 *   switchFunctional(user)
 *     // Checks `user.hasDevProjects === true`
 *     .case({ hasDevProjects: true }, 'developer')
 *     // Checks for deep properties
 *     .case({ devProjectsCount: 0, permissions: { admin: true } }, 'admin')
 *     .default('unknown')
 * ```
 *
 * @example <caption>Returning dynamic values</caption>
 * ```js
 * const getUserType = (user) =>
 *   switchFunctional(user)
 *     .case(isDeveloper, (user) => user.developerType)
 *     .case(isAdmin, (user) => user.adminType)
 *     .default((user) => user.genericType)
 * ```
 */
const switchFunctional = chain(false)

export default switchFunctional