https://grokonez.com/node-js/ways-to-implement-proxy-pattern-in-node-js
Ways to implement Proxy Pattern in Node.js
Sometimes we may want to access indirectly to an object, via a substitute. That substitute is called Proxy. The Proxy Pattern helps us deal with a proxy object and talk to the actual object. In this tutorial, we're gonna look at 2 ways to implement Proxy Pattern in Node.js:
- Using custom Proxy Class
- Using Proxy API
Proxy Pattern Overview
The image above shows that Proxy
and Subject
have the same methods. Proxy
forwards each operation to Subject
, we can improve Subject
's methods with additional pre-processing or post-processing.
Proxy Pattern in Node.js using custom Class
Create Subject class
We create a Bank
class with 3 methods:
– deposit()
increases cash.
– withdraw()
decreases cash.
– total()
returns cash.
Bank.js
class Bank {
constructor() {
this.cash = 0;
}
deposit(amount) {
this.cash += amount;
return this.cash;
}
withdraw(amount) {
if (amount <= this.cash) {
this.cash -= amount;
return true;
} else {
return false;
}
}
total() {
return this.cash;
}
}
module.exports = Bank;
Create custom Proxy class
The Proxy
class also have 3 methods: deposit()
, withdraw()
, total()
. Inside each method, we call Subject
's methods with additional process.
Notice that we need initiate Bank
object in constructor()
method.
BankProxy.js
More at:
https://grokonez.com/node-js/ways-to-implement-proxy-pattern-in-node-js
Ways to implement Proxy Pattern in Node.js
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