export a 'createSelectorWithCacheSize' function, added more notes to …

…the README

README.md

@@ -417,6 +417,7 @@ Takes one or more selectors, or an array of selectors, computes their values and
 `createSelector` determines if the value returned by an input-selector has changed between calls using reference equality (`===`). Inputs to selectors created with `createSelector` should be immutable.
 
 Selectors created with `createSelector` have a cache size of 1. This means they always recalculate when the value of an input-selector changes, as a selector only stores the preceding value of each input-selector.
+Most of the time this is all you need, but you can use `createSelectorWithCacheSize` to set a larger cache size. You can also create [a custom selector creator]((#customize-equalitycheck-for-defaultmemoize) to also configure the equality check.
 
 ```js
 const mySelector = createSelector(
@@ -457,13 +458,16 @@ const totalSelector = createSelector(
 
 ```
 
+### createSelectorWithCacheSize(cacheSize, ...inputSelectors | [inputSelectors], resultFunc)
+
+Same as createSelector, except you can configure the cache size using the first argument. When the cache is full, it will overwrite the oldest value.
+
+
 ### defaultMemoize(func, equalityCheck = defaultEqualityCheck, cacheSize = 1)
 
 `defaultMemoize` memoizes the function passed in the func parameter. It is the memoize function used by `createSelector`.
 
-`defaultMemoize` has a default cache size of 1. This means it always recalculates when the value of an argument changes.
-
-You can specify a cache size larger than one, and the selector will store the last n results. When the cache is full, it will replace the oldest result with the new result. It does not care about order in which results are accessed, only created.
+`defaultMemoize` has a default cache size of 1. This means it always recalculates when the value of an argument changes. You can specify a larger cache size to store multiple results. When the cache is full, it will overwrite the oldest result.
 
 `defaultMemoize` determines if an argument has changed by calling the `equalityCheck` function. As `defaultMemoize` is designed to be used with immutable data, the default `equalityCheck` function checks for changes using reference equality:
 
@@ -507,6 +511,18 @@ customMemoize(resultFunc, option1, option2, option3)
 
 Here are some examples of how you might use `createSelectorCreator`:
 
+#### Customize `cacheSize` for `defaultMemoize`
+
+```js
+import { createSelectorCreator, defaultMemoize, defaultEqualityCheck } from 'reselect'
+
+const createDeepEqualSelector = createSelectorCreator(
+  defaultMemoize,
+  defaultEqualityCheck,
+  5  // cache up to 5 results
+)
+```
+
 #### Customize `equalityCheck` for `defaultMemoize`
 
 ```js

src/index.js

@@ -150,6 +150,9 @@ export function createSelectorCreator(memoize, ...memoizeOptions) {
 }
 
 export const createSelector = createSelectorCreator(defaultMemoize)
+export const createSelectorWithCacheSize = (cacheSize, ...args) => (
+  createSelectorCreator(defaultMemoize, defaultEqualityCheck, cacheSize)
+)(...args)
 
 export function createStructuredSelector(selectors, selectorCreator = createSelector) {
   if (typeof selectors !== 'object') {

test/test_selector.js

@@ -1,8 +1,8 @@
 // TODO: Add test for React Redux connect function
 
 import chai from 'chai'
-import { createSelector, createSelectorCreator, defaultMemoize,
-  memoizeOne, createStructuredSelector
+import { createSelector, createSelectorWithCacheSize, createSelectorCreator,
+  defaultMemoize, memoizeOne, createStructuredSelector
 } from '../src/index'
 import {  default as lodashMemoize  } from 'lodash.memoize'
 
@@ -99,7 +99,7 @@ suite('selector', () => {
       return // don't run performance tests for coverage
     }
 
-    const selector = createSelectorCreator(defaultMemoize, undefined, 2)(
+    const selector = createSelectorWithCacheSize(2,
       state => state.a,
       state => state.b,
       (a, b) => a + b
@@ -152,7 +152,7 @@ suite('selector', () => {
       return // don't run performance tests for coverage
     }
 
-    const selector = createSelectorCreator(defaultMemoize, undefined, 2)(
+    const selector = createSelectorWithCacheSize(2,
       state => state.a,
       state => state.b,
       (a, b) => a + b
@@ -514,9 +514,7 @@ suite('selector', () => {
   })
 
   test('defaultMemoize with cacheSize 2', () => {
-    const createSelectorWithCacheSize2 = createSelectorCreator(defaultMemoize, undefined, 2 )
-
-    const selector = createSelectorWithCacheSize2([
+    const selector = createSelectorWithCacheSize(2, [
       (state) => state.num
     ], (num) => num * num)
 
@@ -569,9 +567,7 @@ suite('selector', () => {
   })
 
   test('defaultMemoize with cacheSize 5', () => {
-    const createSelectorWithCacheSize5 = createSelectorCreator(defaultMemoize, undefined, 5)
-
-    const selector = createSelectorWithCacheSize5([
+    const selector = createSelectorWithCacheSize(5, [
       (state) => state.num
     ], (num) => num * num)