aadd structural adapter js

Signed-off-by: Nimit <nimitagg95@gmail.com>

Author: nimit95

Creational/factoryMethod.js

@@ -68,5 +68,5 @@ class ClientHTTP extends ClientTcp {
  }
 }
 
-let c = new ClientHTTP;
+let c = new ClientHTTP();
 c.main();

README.md

@@ -13,3 +13,13 @@ Creational patterns are ones that create objects for you, rather than having you
 - **Prototype:** specify the kinds of objects to create using a prototypical instance, and create new objects from the 'skeleton' of an existing object, thus boosting performance and keeping memory footprints to a minimum.
 - **Singleton:** ensure a class has only one instance, and provide a global point of access to it.
 
+### Structural Patterns
+These concern class and object composition. They use inheritance to compose interfaces and define ways to compose objects to obtain new functionality.
+
+- **Adapter:** allows classes with incompatible interfaces to work together by wrapping its own interface around that of an already existing class.
+- **Bridge:** decouples an abstraction from its implementation so that the two can vary independently.
+- **Composite:** composes zero-or-more similar objects so that they can be manipulated as one object.
+- **Decorator:** dynamically adds/overrides behaviour in an existing method of an object.
+- **Facade:** provides a simplified interface to a large body of code.
+- **Flyweight:** reduces the cost of creating and manipulating a large number of similar objects.
+- **Proxy:** provides a placeholder for another object to control access, reduce cost, and reduce complexity.

Structural/adapter.js

@@ -0,0 +1,41 @@
+// fs is the adaptee class
+const fs = require('fs');
+
+// delegator class
+class fsDelegator {
+ read() {
+ return new Error("Please implement read method!");
+ }
+}
+/**
+ * Adapter class implements the delegate
+ * Converts fs callbacks to fs promisified
+ */
+class fsAdapter extends fsDelegator {
+ read(path) {
+ return new Promise((resolve, reject) => {
+ // eslint-disable-next-line node/prefer-promises/fs
+ fs.readFile(__dirname + "/" + path, (err, buf) => {
+ if(err) {
+ return reject(err);
+ }
+ resolve(buf.toString());
+ });
+ });
+ }
+}
+
+class Client {
+ constructor() {
+ this.setDelegate();
+ }
+ async reader() {
+ return this._fsDelegate.read("adapter.js");
+ }
+ setDelegate() {
+ this._fsDelegate = new fsAdapter();
+ }
+}
+
+const client = new Client();
+client.reader().then(res => console.log("Reading " + res));

buildDocs.js

@@ -4,15 +4,24 @@ const nPath = require('path');
 /* Path Constants */
 const DOCS_FILE = './docs.md';
 
-const sections = [{
- name: 'Creational', topics: [
- { name: 'abstractFactory', path: './Creational' },
- { name: 'builder', path: './Creational' },
- { name: 'factoryMethod', path: './Creational' },
- { name: 'prototype', path: './Creational' },
- { name: 'singleton', path: './Creational' }
- ]
-}];
+const sections = [
+ {
+ name: 'Creational', 
+ topics: [
+ { name: 'abstractFactory', path: './Creational' },
+ { name: 'builder', path: './Creational' },
+ { name: 'factoryMethod', path: './Creational' },
+ { name: 'prototype', path: './Creational' },
+ { name: 'singleton', path: './Creational' }
+ ]
+ },
+ {
+ name: 'Structural', 
+ topics: [
+ { name: 'adapter', path: './Structural' }
+ ]
+ }
+];
 
 /* Utility functions */
 const stripPunctuation = (str) =>

docs.md

@@ -7,6 +7,9 @@
 * [Prototype](#prototype)
 * [Singleton](#singleton)
 
+**[ Structural](#structural)**
+* [Adapter](#adapter)
+
 
 
 ## Creational
@@ -232,7 +235,7 @@ class ClientHTTP extends ClientTcp {
  }
 }
 
-let c = new ClientHTTP;
+let c = new ClientHTTP();
 c.main();
 ```
 
@@ -292,4 +295,53 @@ Server.getInstance().status();
 ```
 
 
+## Structural
+### Adapter
+##### adapter.js
+```Javascript
+// fs is the adaptee class
+const fs = require('fs');
+
+// delegator class
+class fsDelegator {
+ read() {
+ return new Error("Please implement read method!");
+ }
+}
+/**
+ * Adapter class implements the delegate
+ * Converts fs callbacks to fs promisified
+ */
+class fsAdapter extends fsDelegator {
+ read(path) {
+ return new Promise((resolve, reject) => {
+ // eslint-disable-next-line node/prefer-promises/fs
+ fs.readFile(__dirname + "/" + path, (err, buf) => {
+ if(err) {
+ return reject(err);
+ }
+ resolve(buf.toString());
+ });
+ });
+ }
+}
+
+class Client {
+ constructor() {
+ this.setDelegate();
+ }
+ async reader() {
+ return this._fsDelegate.read("adapter.js");
+ }
+ setDelegate() {
+ this._fsDelegate = new fsAdapter();
+ }
+}
+
+const client = new Client();
+client.reader().then(res => console.log("Reading " + res));
+
+```
+
+