Discussion on: Design Patterns Everyday

Nice Article Anurag. I need to refresh my knowledge in patterns so I will read one per day (and leave my comments, I hope that is ok!)

Day 1:Abstract Factory Pattern:
It would be good to have a summary before the ending. The most important thing to mention here:

"The benefit of this pattern is that no matter which family/factory your guiFactory instance is, you will ALWAYS implement using this code:
createButton(); and button.render());

This is where the flexibility of pattern comes in."

Day 2: Builder pattern
Missing the final step:
_"When you have finished building your object, you should call build() to instantiate:
let myTruck = truck.build();
let mySedan = sedan.build();"

Day 4: Singleton
You can also implement a lazy initialization singleton. Same concept, but singleton instantiation it's delayed until the object is required. This can improve performance in some cases.

class LazySingleton {
name = "Im a LazySingleton";
static instance;
static getInstance() {
if(!instance){
this.instance = new LazySingleton();
}
return instance;
}
}
// instance does not exist yet
instance2 = LazySingleton.getInstance();
// instance was just created
console.log(instance.name);