GoF Strategy

Strategy.js

class Shipping {
    constructor() {
        this.method = "";
    }
    setStrategy (method) {
        this.method = method;
    }
    calculate (box) {
        return this.method.calculate(box);
    }
};

class Air {
    calculate (box) {
        // calculations...
        return "$45.95";
    }
}

class Sea {
    calculate (box) {
        // calculations...
        return "$39.40";
    }
}

class Land {
    calculate (box) {
        // calculations...
        return "$43.20";
    }
};


const box = { from: "76712", to: "10012", weigth: "lkg" };

// the 3 strategies
const air = new Air();
const sea = new Sea();
const land = new Land();

const shipping = new Shipping();

shipping.setStrategy(air);
console.log("Air Strategy: " + shipping.calculate(box));
shipping.setStrategy(sea);
console.log("Sea Strategy: " + shipping.calculate(box));
shipping.setStrategy(land);
console.log("Land Strategy: " + shipping.calculate(box));

// Air Strategy: $45.95
// Sea Strategy: $39.40
// Land Strategy: $43.20