Notes

Behavioral

Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm exist very independently from clients that use it.
strategy-pattern
/**
* The Context defines the interface of interest to clients.
*/
class Context {
​
private strategy: Strategy;
​
constructor(strategy: Strategy) {
this.strategy = strategy;
}
​
public setStrategy(strategy: Strategy) {
this.strategy = strategy;
}
​
public doSomeBusinessLogic(): void {
console.log('Context: Sorting data using the strategy (not sure how it\'ll do it)');
const result = this.strategy.doAlgorithm(['a', 'b', 'c', 'd', 'e']);
console.log(result.join(','));
}
}
​
interface Strategy {
doAlgorithm(data: string[]): string[];
}
​
class ConcreteStrategyA implements Strategy {
public doAlgorithm(data: string[]): string[] {
return data.sort();
}
}
​
class ConcreteStrategyB implements Strategy {
public doAlgorithm(data: string[]): string[] {
return data.reverse();
}
}
​
const context = new Context(new ConcreteStrategyA());
console.log('Client: Strategy is set to normal sorting.');
context.doSomeBusinessLogic();
​
console.log('');
​
console.log('Client: Strategy is set to reverse sorting.');
context.setStrategy(new ConcreteStrategyB());
context.doSomeBusinessLogic();

β€‹πŸ”—β€‹

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