Do not use window for globals. Expose clear/disable functions in utils/memoize

perf/benchmarks/memoize-util/index.js

@@ -2,8 +2,6 @@ const { default: memoize } = require('../../../lib/utils/memoize')
 
 module.exports = {
   setup(state) {
-    window.__NO_MEMOIZE = false
-
     let obj = {
       fibonacci(n = 20) {
         if (n === 0 || n === 1) {
@@ -20,11 +18,5 @@ module.exports = {
 
   run(obj) {
     obj.fibonacci()
-    // Clear cache for next runs
-    delete obj.__cache
-  },
-
-  teardown() {
-    window.__NO_MEMOIZE = true
   }
 }

perf/index.js

@@ -20,9 +20,9 @@ const fs = require('fs')
 const _ = require('lodash')
 const readMetadata = require('read-metadata')
 const { Raw } = require('..')
-const { resolve } = require('path')
+const memoize = require('../lib/utils/memoize')
 
-window.__NO_MEMOIZE = true
+const { resolve } = require('path')
 
 const DEFAULT_BENCHMARK = {
   setup(state) { return state },
@@ -77,6 +77,7 @@ function runBenchmarks() {
     // Setup global scope for this benchmark
     global.setScope(benchmarkName, {
       Raw,
+      memoize,
       benchmark,
       input
     })
@@ -93,15 +94,11 @@ function runBenchmarks() {
 
       // Time spent in setup is not taken into account
       setup() {
-        // Create as much independant Slate.State as needed, to avoid
-        // memoization between calls to `fn`
         const scope = global.getScope()
-
-        const state =
-              // Each benchmark is given the chance to do its own setup
-              scope.benchmark.setup(
-                scope.Raw.deserialize(scope.input, { terse: true })
-              )
+        // Each benchmark is given the chance to do its own setup
+        const state = scope.benchmark.setup(
+          scope.Raw.deserialize(scope.input, { terse: true })
+        )
       },
 
       // Because of the way BenchmarkJS compiles the functions,
@@ -109,7 +106,8 @@ function runBenchmarks() {
 
       fn() {
         scope.benchmark.run(state) // eslint-disable-line no-undef
-        // Next call will use another State instance
+        // Clear memoized values between each run
+        scope.memoize.__clear() // eslint-disable-line no-undef
       },
 
       onComplete() {

src/utils/memoize.js

@@ -1,5 +1,18 @@
 /* global Map */
 
+import IS_DEV from './is-dev'
+
+/**
+ * This module serves to memoize methods on immutable instances.
+ */
+
+// Global: True if memoization should is enabled. Only effective in DEV mode
+let ENABLED = true
+
+// Global: Changing this cache key will clear all previous cached
+// results. Only effective in DEV mode
+let CACHE_KEY = 0
+
 /**
  * The leaf node of a cache tree. Used to support variable argument length.
  *
@@ -42,8 +55,15 @@ function memoize(object, properties) {
     }
 
     object[property] = function (...args) {
-      if (window.__NO_MEMOIZE) {
-        return original.apply(this, args)
+      if (IS_DEV) {
+        if (!ENABLED) {
+          // Memoization disabled
+          return original.apply(this, args)
+        } else if (CACHE_KEY !== this.__cache_key) {
+          // Previous caches must be cleared
+          this.__cache_key = CACHE_KEY
+          this.__cache = new Map()
+        }
       }
 
       const keys = [property, ...args]
@@ -118,8 +138,34 @@ function getIn(map, keys) {
   return childMap.get(LEAF)
 }
 
+/**
+ * In DEV mode, clears the previously memoized values, globally.
+ * @return {Void}
+ */
+
+function __clear() {
+  CACHE_KEY++
+  if (CACHE_KEY >= Number.MAX_SAFE_INTEGER) {
+    CACHE_KEY = 0
+  }
+}
+
+/**
+ * In DEV mode, enable or disable the use of memoize values, globally.
+ * @param {Boolean} enabled
+ * @return {Void}
+ */
+
+function __enable(enabled) {
+  ENABLED = enabled
+}
+
 /**
  * Export.
  */
 
-export default memoize
+export {
+  memoize as default,
+  __clear,
+  __enable
+}