jpcasa
12/20/2018 - 1:52 AM

Bridge Structural Design Pattern

Bridge Structural Design Pattern

README.md
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Real world example

Consider you have a website with different pages and you are supposed to allow the user to change the theme. What would you do? Create multiple copies of each of the pages for each of the themes or would you just create separate theme and load them based on the user's preferences? Bridge pattern allows you to do the second i.e.

In Plain Words

Bridge pattern is about preferring composition over inheritance. Implementation details are pushed from a hierarchy to another object with a separate hierarchy.

Wikipedia says

The bridge pattern is a design pattern used in software engineering that is meant to "decouple an abstraction from its implementation so that the two can vary independently"

main.js
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/*
Webpage interface :

constructor(theme)
getContent()
*/

class About{ 
    constructor(theme) {
        this.theme = theme
    }
    
    getContent() {
        return "About page in " + this.theme.getColor()
    }
}

class Careers{
   constructor(theme) {
       this.theme = theme
   }
   
   getContent() {
       return "Careers page in " + this.theme.getColor()
   } 
}

/*
Theme interface :

getColor()
*/

class DarkTheme{
    getColor() {
        return 'Dark Black'
    }
}
class LightTheme{
    getColor() {
        return 'Off white'
    }
}
class AquaTheme{
    getColor() {
        return 'Light blue'
    }
}


// IMPLEMENTATION
const darkTheme = new DarkTheme()

const about = new About(darkTheme)
const careers = new Careers(darkTheme)

console.log(about.getContent() )// "About page in Dark Black"
console.log(careers.getContent() )// "Careers page in Dark Black"