planning

node_modules/reselect/es/defaultMemoize.js

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+// Cache implementation based on Erik Rasmussen's `lru-memoize`:
+// https://github.com/erikras/lru-memoize
+var NOT_FOUND = 'NOT_FOUND';
+
+function createSingletonCache(equals) {
+  var entry;
+  return {
+    get: function get(key) {
+      if (entry && equals(entry.key, key)) {
+        return entry.value;
+      }
+
+      return NOT_FOUND;
+    },
+    put: function put(key, value) {
+      entry = {
+        key: key,
+        value: value
+      };
+    },
+    getEntries: function getEntries() {
+      return entry ? [entry] : [];
+    },
+    clear: function clear() {
+      entry = undefined;
+    }
+  };
+}
+
+function createLruCache(maxSize, equals) {
+  var entries = [];
+
+  function get(key) {
+    var cacheIndex = entries.findIndex(function (entry) {
+      return equals(key, entry.key);
+    }); // We found a cached entry
+
+    if (cacheIndex > -1) {
+      var entry = entries[cacheIndex]; // Cached entry not at top of cache, move it to the top
+
+      if (cacheIndex > 0) {
+        entries.splice(cacheIndex, 1);
+        entries.unshift(entry);
+      }
+
+      return entry.value;
+    } // No entry found in cache, return sentinel
+
+
+    return NOT_FOUND;
+  }
+
+  function put(key, value) {
+    if (get(key) === NOT_FOUND) {
+      // TODO Is unshift slow?
+      entries.unshift({
+        key: key,
+        value: value
+      });
+
+      if (entries.length > maxSize) {
+        entries.pop();
+      }
+    }
+  }
+
+  function getEntries() {
+    return entries;
+  }
+
+  function clear() {
+    entries = [];
+  }
+
+  return {
+    get: get,
+    put: put,
+    getEntries: getEntries,
+    clear: clear
+  };
+}
+
+export var defaultEqualityCheck = function defaultEqualityCheck(a, b) {
+  return a === b;
+};
+export function createCacheKeyComparator(equalityCheck) {
+  return function areArgumentsShallowlyEqual(prev, next) {
+    if (prev === null || next === null || prev.length !== next.length) {
+      return false;
+    } // Do this in a for loop (and not a `forEach` or an `every`) so we can determine equality as fast as possible.
+
+
+    var length = prev.length;
+
+    for (var i = 0; i < length; i++) {
+      if (!equalityCheck(prev[i], next[i])) {
+        return false;
+      }
+    }
+
+    return true;
+  };
+}
+// defaultMemoize now supports a configurable cache size with LRU behavior,
+// and optional comparison of the result value with existing values
+export function defaultMemoize(func, equalityCheckOrOptions) {
+  var providedOptions = typeof equalityCheckOrOptions === 'object' ? equalityCheckOrOptions : {
+    equalityCheck: equalityCheckOrOptions
+  };
+  var _providedOptions$equa = providedOptions.equalityCheck,
+      equalityCheck = _providedOptions$equa === void 0 ? defaultEqualityCheck : _providedOptions$equa,
+      _providedOptions$maxS = providedOptions.maxSize,
+      maxSize = _providedOptions$maxS === void 0 ? 1 : _providedOptions$maxS,
+      resultEqualityCheck = providedOptions.resultEqualityCheck;
+  var comparator = createCacheKeyComparator(equalityCheck);
+  var cache = maxSize === 1 ? createSingletonCache(comparator) : createLruCache(maxSize, comparator); // we reference arguments instead of spreading them for performance reasons
+
+  function memoized() {
+    var value = cache.get(arguments);
+
+    if (value === NOT_FOUND) {
+      // @ts-ignore
+      value = func.apply(null, arguments);
+
+      if (resultEqualityCheck) {
+        var entries = cache.getEntries();
+        var matchingEntry = entries.find(function (entry) {
+          return resultEqualityCheck(entry.value, value);
+        });
+
+        if (matchingEntry) {
+          value = matchingEntry.value;
+        }
+      }
+
+      cache.put(arguments, value);
+    }
+
+    return value;
+  }
+
+  memoized.clearCache = function () {
+    return cache.clear();
+  };
+
+  return memoized;
+}