Behavioural Pattern - Chain of Responsibility

ChainOfResponsibility.js

class CumulativeSum {
  constructor(intialValue = 0) {
    this.sum = intialValue;
  }

  add(value) {
    this.sum += value;
    return this;
  }
}

// usage
const sum1 = new CumulativeSum();
console.log(sum1.add(10).add(2).add(50).sum); // 62


const sum2 = new CumulativeSum(10);
console.log(sum2.add(10).add(20).add(5).sum); // 45