"use strict";
|
|
Object.defineProperty(exports, "__esModule", {
|
value: true
|
});
|
exports["default"] = void 0;
|
|
function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }
|
|
function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }
|
|
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
|
|
// https://medium.com/dsinjs/implementing-lru-cache-in-javascript-94ba6755cda9
|
var Node = /*#__PURE__*/_createClass(function Node(key, value) {
|
var next = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;
|
var prev = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : null;
|
|
_classCallCheck(this, Node);
|
|
this.key = key;
|
this.value = value;
|
this.next = next;
|
this.prev = prev;
|
});
|
|
var LRUCache = /*#__PURE__*/function () {
|
//set default limit of 10 if limit is not passed.
|
function LRUCache() {
|
var limit = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 10;
|
|
_classCallCheck(this, LRUCache);
|
|
this.size = 0;
|
this.limit = limit;
|
this.head = null;
|
this.tail = null;
|
this.cache = {};
|
} // Write Node to head of LinkedList
|
// update cache with Node key and Node reference
|
|
|
_createClass(LRUCache, [{
|
key: "put",
|
value: function put(key, value) {
|
this.ensureLimit();
|
|
if (!this.head) {
|
this.head = this.tail = new Node(key, value);
|
} else {
|
var node = new Node(key, value, this.head);
|
this.head.prev = node;
|
this.head = node;
|
} //Update the cache map
|
|
|
this.cache[key] = this.head;
|
this.size++;
|
} // Read from cache map and make that node as new Head of LinkedList
|
|
}, {
|
key: "get",
|
value: function get(key) {
|
if (this.cache[key]) {
|
var value = this.cache[key].value; // node removed from it's position and cache
|
|
this.remove(key); // write node again to the head of LinkedList to make it most recently used
|
|
this.put(key, value);
|
return value;
|
}
|
|
console.log("Item not available in cache for key ".concat(key));
|
}
|
}, {
|
key: "ensureLimit",
|
value: function ensureLimit() {
|
if (this.size === this.limit) {
|
this.remove(this.tail.key);
|
}
|
}
|
}, {
|
key: "remove",
|
value: function remove(key) {
|
var node = this.cache[key];
|
|
if (node.prev !== null) {
|
node.prev.next = node.next;
|
} else {
|
this.head = node.next;
|
}
|
|
if (node.next !== null) {
|
node.next.prev = node.prev;
|
} else {
|
this.tail = node.prev;
|
}
|
|
delete this.cache[key];
|
this.size--;
|
}
|
}, {
|
key: "clear",
|
value: function clear() {
|
this.head = null;
|
this.tail = null;
|
this.size = 0;
|
this.cache = {};
|
} // // Invokes the callback function with every node of the chain and the index of the node.
|
// forEach(fn) {
|
// let node = this.head;
|
// let counter = 0;
|
// while (node) {
|
// fn(node, counter);
|
// node = node.next;
|
// counter++;
|
// }
|
// }
|
// // To iterate over LRU with a 'for...of' loop
|
// *[Symbol.iterator]() {
|
// let node = this.head;
|
// while (node) {
|
// yield node;
|
// node = node.next;
|
// }
|
// }
|
|
}]);
|
|
return LRUCache;
|
}();
|
|
exports["default"] = LRUCache;
|
//# sourceMappingURL=LRUCache.js.map
|
