One of the pullrequests of the HacktoberFest 2024

STL.md

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+# JavaScript Standard Template Library (STL) Overview
+
+This README provides an overview of the core data structures and methods available in JavaScript that are commonly used for various programming tasks. While JavaScript does not have a dedicated Standard Template Library (STL) like C++, it provides several built-in objects that can be used similarly.
+
+## 1. Arrays
+
+### Description
+Arrays are used to store multiple values in a single variable.
+
+### Key Methods
+- **Creation**
+  - `let arr = [];` // empty array
+  - `let arr = [1, 2, 3];` // array with elements
+- **Common Methods**
+  - `arr.push(element)` - Adds an element to the end of the array.
+  - `arr.pop()` - Removes the last element from the array.
+  - `arr.shift()` - Removes the first element from the array.
+  - `arr.unshift(element)` - Adds an element to the beginning of the array.
+  - `arr.slice(start, end)` - Returns a shallow copy of a portion of an array.
+  - `arr.map(callback)` - Creates a new array with the results of calling a provided function on every element.
+  - `arr.filter(callback)` - Creates a new array with all elements that pass the test implemented by the provided function.
+  - `arr.reduce(callback, initialValue)` - Executes a reducer function on each element of the array, resulting in a single output value.
+
+## 2. Objects
+
+### Description
+Objects are collections of key-value pairs and can represent complex data structures.
+
+### Key Methods
+- **Creation**
+  - `let obj = {};` // empty object
+  - `let obj = { key: 'value' };` // object with properties
+- **Common Methods**
+  - `Object.keys(obj)` - Returns an array of a given object's own property names.
+  - `Object.values(obj)` - Returns an array of a given object's own enumerable property values.
+  - `Object.entries(obj)` - Returns an array of a given object's own enumerable string-keyed property [key, value] pairs.
+  - `Object.assign(target, ...sources)` - Copies the values of all enumerable own properties from one or more source objects to a target object.
+
+## 3. Sets
+
+### Description
+Sets are collections of values where each value must be unique.
+
+### Key Methods
+- **Creation**
+  - `let mySet = new Set();`
+  - `let mySet = new Set([1, 2, 3]);`
+- **Common Methods**
+  - `mySet.add(value)` - Adds a new element to the Set.
+  - `mySet.delete(value)` - Removes an element from the Set.
+  - `mySet.has(value)` - Returns a boolean indicating whether an element is present.
+  - `mySet.clear()` - Removes all elements from the Set.
+  - `mySet.size` - Returns the number of elements in the Set.
+
+## 4. Maps
+
+### Description
+Maps are collections of keyed data items, where keys can be of any type.
+
+### Key Methods
+- **Creation**
+  - `let myMap = new Map();`
+  - `let myMap = new Map([['key1', 'value1'], ['key2', 'value2']]);`
+- **Common Methods**
+  - `myMap.set(key, value)` - Adds a new element with a specified key and value.
+  - `myMap.get(key)` - Returns the value associated with the specified key.
+  - `myMap.delete(key)` - Removes the specified key and its associated value.
+  - `myMap.has(key)` - Returns a boolean indicating whether the specified key exists.
+  - `myMap.clear()` - Removes all elements from the Map.
+  - `myMap.size` - Returns the number of key-value pairs in the Map.
+
+## 5. WeakSets
+
+### Description
+WeakSets are collections of objects, where each object is held weakly (i.e., garbage collected if there are no other references).
+
+### Key Methods
+- **Creation**
+  - `let myWeakSet = new WeakSet();`
+- **Common Methods**
+  - `myWeakSet.add(value)` - Adds an object to the WeakSet.
+  - `myWeakSet.delete(value)` - Removes an object from the WeakSet.
+  - `myWeakSet.has(value)` - Returns a boolean indicating whether the object is in the WeakSet.
+
+## 6. WeakMaps
+
+### Description
+WeakMaps are collections of key-value pairs, where keys are held weakly.
+
+### Key Methods
+- **Creation**
+  - `let myWeakMap = new WeakMap();`
+- **Common Methods**
+  - `myWeakMap.set(key, value)` - Sets the value for the key in the WeakMap.
+  - `myWeakMap.get(key)` - Returns the value associated with the key.
+  - `myWeakMap.delete(key)` - Removes the key and its associated value.
+  - `myWeakMap.has(key)` - Returns a boolean indicating whether the key exists.
+
+## Conclusion
+
+This document outlines the fundamental data structures and methods available in JavaScript, which provide similar functionality to the Standard Template Library (STL) found in other programming languages. These built-in objects can be utilized for a wide range of programming tasks, making JavaScript a versatile and powerful language for web development.