redux-keto example

index.js

const keto = require('redux-keto')
const buildReducer = keto.buildReducer

const maxCount = (state = 0, action) => 
	action.type === 'CHANGE_MAX_COUNT' 
	? action.payload 
	: state

const counter = (state = 0, action, next) =>
  Math.min(next.maxCount, action.type === 'INCREMENT' ? state + action.payload : state)

const rootReducer = buildReducer({ maxCount, counter })

state = rootReducer(undefined, {type: 'init'})
console.log(state)

state = rootReducer(state, {type: 'INCREMENT', payload: 1})
console.log(state)

state = rootReducer(state, {type: 'CHANGE_MAX_COUNT', payload: 1})
console.log(state)

state = rootReducer(state, {type: 'INCREMENT', payload: 1})
console.log(state)

state = rootReducer(state, {type: 'CHANGE_MAX_COUNT', payload: 0})
console.log(state)

state = rootReducer(state, {type: 'INCREMENT', payload: 1})
console.log(state)

minified.js

setTimeout(function(){
;require=(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({"redux-keto":[function(require,module,exports){
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

// Special property that only our wrappers will have:
var wrapperMagic = 'redux-keto wrapper';

/**
 * Makes a collection of lazy getters for a key-value state slice.
 * The actual wrapper object inherits from this prototype.
 */
function makeWrapperProto (keys, makeReducer, makeNext) {
  var wrapperProto = Object.create(null);
  var loop = function () {
    var key = list[i];

    var reducer = makeReducer(key);

    Object.defineProperty(wrapperProto, key, {
      configurable: true,
      enumerable: true,
      get: function get () {
        var wrapper = this;
        var stash = wrapper[wrapperMagic];

        // If we are already running, this is a problem!
        if (stash.running[key]) {
          var e = new ReferenceError(
            ("Reducer '" + key + "' depends on its own result")
          );
          e.name = 'ReduxKetoCircularReferenceError';
          throw e
        }
        stash.running[key] = true;

        // Evaluate the reducer:
        try {
          var out = reducer(
            stash.state[key],
            stash.action,
            makeNext(stash.next, wrapper, key),
            makeNext(stash.prev, stash.state, key)
          );
          if (out === undefined) {
            throw new TypeError(("Reducer '" + key + "' returned undefined"))
          }
          Object.defineProperty(wrapper, key, {
            configurable: true,
            enumerable: true,
            writable: false,
            value: out
          });
          return out
        } finally {
          stash.running[key] = false;
        }
      }
    });
  };

  for (var i = 0, list = keys; i < list.length; i += 1) loop();

  return wrapperProto
}

/**
 * Makes a lazy wrapper object for a key-value state slice.
 */
function makeWrapper (wrapperProto, state, action, next, prev) {
  var wrapper = Object.create(wrapperProto);
  Object.defineProperty(wrapper, wrapperMagic, {
    configurable: true,
    enumerable: false,
    writable: false,
    value: { state: state, action: action, next: next, prev: prev, running: {} }
  });

  return wrapper
}

/**
 * Flattens a lazy key-value wrapper into a plain-old object
 * with the current state as its properties.
 */
function flattenWrapper (state, wrapper) {
  if ( state === void 0 ) state = {};

  // If it's not a wrapper, we are done:
  if (wrapper === null || wrapper[wrapperMagic] == null) { return wrapper }

  // Diff the old and new states:
  var keys = Object.keys(Object.getPrototypeOf(wrapper));
  var unchanged = Object.keys(state).length === keys.length;
  for (var i = 0, list = keys; i < list.length; i += 1) {
    var key = list[i];

    Object.defineProperty(wrapper, key, {
      configurable: false,
      enumerable: true,
      writable: false,
      value: flattenWrapper(state[key], wrapper[key])
    });
    if (wrapper[key] !== state[key]) {
      unchanged = false;
    }
  }

  // If nothing changed, just return the previous state:
  if (unchanged) { return state }

  delete wrapper[wrapperMagic];
  return wrapper
}

function makeNextDefault (next, children, id) {
  return next !== void 0 ? next : children
}

/**
 * Combines several reducers into one.
 */
function buildReducer (reducerMap, makeNext) {
  if ( makeNext === void 0 ) makeNext = makeNextDefault;

  // Validate argument types:
  if (typeof reducerMap !== 'object' || reducerMap === null) {
    throw new TypeError('The reducer map must be an object.')
  }
  var keys = Object.keys(reducerMap);
  for (var i = 0, list = keys; i < list.length; i += 1) {
    var key = list[i];

    if (typeof reducerMap[key] !== 'function') {
      throw new TypeError('Reducers must be functions.')
    }
  }

  // Build the wrapper:
  var wrapperProto = makeWrapperProto(keys, function (key) { return reducerMap[key]; }, makeNext);

  // Build the default state:
  var defaultState = {};
  for (var i$1 = 0, list$1 = keys; i$1 < list$1.length; i$1 += 1) {
    var key$1 = list$1[i$1];

    defaultState[key$1] = reducerMap[key$1].defaultState;
  }

  function builtReducer (state, action, next, prev) {
    if ( state === void 0 ) state = defaultState;

    var wrapper = makeWrapper(wrapperProto, state, action, next, prev);

    // If we are the topmost fat reducer, flatten the wrappers:
    return next === void 0 ? flattenWrapper(state, wrapper) : wrapper
  }
  builtReducer.defaultState = defaultState;

  return builtReducer
}

function filterActionsDefault (action, next) {
  return action
}

function filterNextDefault (next) {
  return next
}

/**
 * Filters the next and actions going into a fat reducer.
 */
function filterReducer (
  reducer,
  filterAction,
  filterNext
) {
  if ( filterAction === void 0 ) filterAction = filterActionsDefault;
  if ( filterNext === void 0 ) filterNext = filterNextDefault;

  var defaultState = reducer.defaultState;

  function filteredReducer (state, action, next, prev) {
    if ( state === void 0 ) state = defaultState;

    var innerAction = filterAction(action, next);
    var innerNext = filterNext(next);
    var innerPrev = filterNext(prev);

    if (!innerAction) { return state }

    var wrapper = reducer(state, innerAction, innerNext, innerPrev);

    // If we are the topmost fat reducer, flatten the wrappers:
    return next === void 0 ? flattenWrapper(state, wrapper) : wrapper
  }
  filteredReducer.defaultState = defaultState;

  return filteredReducer
}

function makeNextDefault$1 (next, children, id) {
  return {
    id: id,
    root: next !== void 0 ? next : children,
    get self () {
      return children[id]
    }
  }
}

var defaultState = {};

/**
 * Applies a reducer to each item of a list.
 * Each reducer manages its own state slice on behalf of the list item.
 */
function mapReducer (reducer, listIds, makeNext) {
  if ( makeNext === void 0 ) makeNext = makeNextDefault$1;

  function mapReducer (state, action, next, prev) {
    if ( state === void 0 ) state = defaultState;

    var ids = listIds(next);

    // Try to recycle our wrapper prototype, if possible:
    var wrapperProto =
      state === defaultState || ids !== listIds(prev)
        ? makeWrapperProto(ids, function (id) { return reducer; }, makeNext)
        : Object.getPrototypeOf(state);

    var wrapper = makeWrapper(wrapperProto, state, action, next, prev);

    // If we are the topmost fat reducer, flatten the wrappers:
    return next === void 0 ? flattenWrapper(state, wrapper) : wrapper
  }
  mapReducer.defaultState = defaultState;

  return mapReducer
}

/**
 * Creates a memoized reducer for derived values.
 * The first aguments are argument filters,
 * which take the next and return an argument to pass to the derivation.
 * The reducer will only run if some of its arguments are not equal ('===').
 */
function memoizeReducer () {
  var arguments$1 = arguments;

  var i = arguments.length - 1;
  var reducer = arguments[i];
  var filters = [];
  while (i-- > 0) { filters[i] = arguments$1[i]; }

  // Type-check the arguments:
  if (typeof reducer !== 'function') {
    throw new TypeError('The reducer must be a function')
  }
  for (var i$1 = 0, list = filters; i$1 < list.length; i$1 += 1) {
    var filter = list[i$1];

    if (typeof filter !== 'function') {
      throw new TypeError('Each argument filter must be a function')
    }
  }

  return function memoizedReducer (
    state,
    action,
    next,
    prev
  ) {
    if ( state === void 0 ) state = reducer.defaultState;

    var clean = state !== undefined;
    var args = [];
    for (var i = 0; i < filters.length; ++i) {
      args[i] = filters[i](next);
      if (clean && args[i] !== filters[i](prev)) { clean = false; }
    }

    return clean ? state : reducer.apply(void 0, args)
  }
}

exports.buildReducer = buildReducer;
exports.filterReducer = filterReducer;
exports.mapReducer = mapReducer;
exports.memoizeReducer = memoizeReducer;


},{}]},{},[])
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i < list.length; i += 1) loop();\n\n  return wrapperProto\n}\n\n/**\n * Makes a lazy wrapper object for a key-value state slice.\n */\nfunction makeWrapper (wrapperProto, state, action, next, prev) {\n  var wrapper = Object.create(wrapperProto);\n  Object.defineProperty(wrapper, wrapperMagic, {\n    configurable: true,\n    enumerable: false,\n    writable: false,\n    value: { state: state, action: action, next: next, prev: prev, running: {} }\n  });\n\n  return wrapper\n}\n\n/**\n * Flattens a lazy key-value wrapper into a plain-old object\n * with the current state as its properties.\n */\nfunction flattenWrapper (state, wrapper) {\n  if ( state === void 0 ) state = {};\n\n  // If it's not a wrapper, we are done:\n  if (wrapper === null || wrapper[wrapperMagic] == null) { return wrapper }\n\n  // Diff the old and new states:\n  var keys = Object.keys(Object.getPrototypeOf(wrapper));\n  var unchanged = Object.keys(state).length === keys.length;\n  for (var i = 0, list = keys; i < list.length; i += 1) {\n    var key = list[i];\n\n    Object.defineProperty(wrapper, key, {\n      configurable: false,\n      enumerable: true,\n      writable: false,\n      value: flattenWrapper(state[key], wrapper[key])\n    });\n    if (wrapper[key] !== state[key]) {\n      unchanged = false;\n    }\n  }\n\n  // If nothing changed, just return the previous state:\n  if (unchanged) { return state }\n\n  delete wrapper[wrapperMagic];\n  return wrapper\n}\n\nfunction makeNextDefault (next, children, id) {\n  return next !== void 0 ? next : children\n}\n\n/**\n * Combines several reducers into one.\n */\nfunction buildReducer (reducerMap, makeNext) {\n  if ( makeNext === void 0 ) makeNext = makeNextDefault;\n\n  // Validate argument types:\n  if (typeof reducerMap !== 'object' || reducerMap === null) {\n    throw new TypeError('The reducer map must be an object.')\n  }\n  var keys = Object.keys(reducerMap);\n  for (var i = 0, list = keys; i < list.length; i += 1) {\n    var key = list[i];\n\n    if (typeof reducerMap[key] !== 'function') {\n      throw new TypeError('Reducers must be functions.')\n    }\n  }\n\n  // Build the wrapper:\n  var wrapperProto = makeWrapperProto(keys, function (key) { return reducerMap[key]; }, makeNext);\n\n  // Build the default state:\n  var defaultState = {};\n  for (var i$1 = 0, list$1 = keys; i$1 < list$1.length; i$1 += 1) {\n    var key$1 = list$1[i$1];\n\n    defaultState[key$1] = reducerMap[key$1].defaultState;\n  }\n\n  function builtReducer (state, action, next, prev) {\n    if ( state === void 0 ) state = defaultState;\n\n    var wrapper = makeWrapper(wrapperProto, state, action, next, prev);\n\n    // If we are the topmost fat reducer, flatten the wrappers:\n    return next === void 0 ? flattenWrapper(state, wrapper) : wrapper\n  }\n  builtReducer.defaultState = defaultState;\n\n  return builtReducer\n}\n\nfunction filterActionsDefault (action, next) {\n  return action\n}\n\nfunction filterNextDefault (next) {\n  return next\n}\n\n/**\n * Filters the next and actions going into a fat reducer.\n */\nfunction filterReducer (\n  reducer,\n  filterAction,\n  filterNext\n) {\n  if ( filterAction === void 0 ) filterAction = filterActionsDefault;\n  if ( filterNext === void 0 ) filterNext = filterNextDefault;\n\n  var defaultState = reducer.defaultState;\n\n  function filteredReducer (state, action, next, prev) {\n    if ( state === void 0 ) state = defaultState;\n\n    var innerAction = filterAction(action, next);\n    var innerNext = filterNext(next);\n    var innerPrev = filterNext(prev);\n\n    if (!innerAction) { return state }\n\n    var wrapper = reducer(state, innerAction, innerNext, innerPrev);\n\n    // If we are the topmost fat reducer, flatten the wrappers:\n    return next === void 0 ? flattenWrapper(state, wrapper) : wrapper\n  }\n  filteredReducer.defaultState = defaultState;\n\n  return filteredReducer\n}\n\nfunction makeNextDefault$1 (next, children, id) {\n  return {\n    id: id,\n    root: next !== void 0 ? next : children,\n    get self () {\n      return children[id]\n    }\n  }\n}\n\nvar defaultState = {};\n\n/**\n * Applies a reducer to each item of a list.\n * Each reducer manages its own state slice on behalf of the list item.\n */\nfunction mapReducer (reducer, listIds, makeNext) {\n  if ( makeNext === void 0 ) makeNext = makeNextDefault$1;\n\n  function mapReducer (state, action, next, prev) {\n    if ( state === void 0 ) state = defaultState;\n\n    var ids = listIds(next);\n\n    // Try to recycle our wrapper prototype, if possible:\n    var wrapperProto =\n      state === defaultState || ids !== listIds(prev)\n        ? makeWrapperProto(ids, function (id) { return reducer; }, makeNext)\n        : Object.getPrototypeOf(state);\n\n    var wrapper = makeWrapper(wrapperProto, state, action, next, prev);\n\n    // If we are the topmost fat reducer, flatten the wrappers:\n    return next === void 0 ? flattenWrapper(state, wrapper) : wrapper\n  }\n  mapReducer.defaultState = defaultState;\n\n  return mapReducer\n}\n\n/**\n * Creates a memoized reducer for derived values.\n * The first aguments are argument filters,\n * which take the next and return an argument to pass to the derivation.\n * The reducer will only run if some of its arguments are not equal ('===').\n */\nfunction memoizeReducer () {\n  var arguments$1 = arguments;\n\n  var i = arguments.length - 1;\n  var reducer = arguments[i];\n  var filters = [];\n  while (i-- > 0) { filters[i] = arguments$1[i]; }\n\n  // Type-check the arguments:\n  if (typeof reducer !== 'function') {\n    throw new TypeError('The reducer must be a function')\n  }\n  for (var i$1 = 0, list = filters; i$1 < list.length; i$1 += 1) {\n    var filter = list[i$1];\n\n    if (typeof filter !== 'function') {\n      throw new TypeError('Each argument filter must be a function')\n    }\n  }\n\n  return function memoizedReducer (\n    state,\n    action,\n    next,\n    prev\n  ) {\n    if ( state === void 0 ) state = reducer.defaultState;\n\n    var clean = state !== undefined;\n    var args = [];\n    for (var i = 0; i < filters.length; ++i) {\n      args[i] = filters[i](next);\n      if (clean && args[i] !== filters[i](prev)) { clean = false; }\n    }\n\n    return clean ? state : reducer.apply(void 0, args)\n  }\n}\n\nexports.buildReducer = buildReducer;\nexports.filterReducer = filterReducer;\nexports.mapReducer = mapReducer;\nexports.memoizeReducer = memoizeReducer;\n//# sourceMappingURL=redux-keto.js.map\n"]}
const keto = require('redux-keto')
const buildReducer = keto.buildReducer

const maxCount = (state = 0, action) => 
	action.type === 'CHANGE_MAX_COUNT' 
	? action.payload 
	: state

const counter = (state = 0, action, next) =>
  Math.min(next.maxCount, action.type === 'INCREMENT' ? state + action.payload : state)

const rootReducer = buildReducer({ maxCount, counter })

state = rootReducer(undefined, {type: 'init'})
console.log(state)

state = rootReducer(state, {type: 'INCREMENT', payload: 1})
console.log(state)

state = rootReducer(state, {type: 'CHANGE_MAX_COUNT', payload: 1})
console.log(state)

state = rootReducer(state, {type: 'INCREMENT', payload: 1})
console.log(state)

state = rootReducer(state, {type: 'CHANGE_MAX_COUNT', payload: 0})
console.log(state)

state = rootReducer(state, {type: 'INCREMENT', payload: 1})
console.log(state)
;}, 0)

package.json

{
  "name": "requirebin-sketch",
  "version": "1.0.0",
  "dependencies": {
    "redux-keto": "0.3.2"
  }
}

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page-head.html

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requirebin.md

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