CODEWITHSUNDEEP
javascript
Forest
Forest

Reputation: 51

Why does it output undefined?

Here is my code:

var arr = [];
class Art {
  constructor() {
    this.values = Array();
  }
  add(date, amount, currency, product) {
    this.values.push([date, amount, currency, product].toString());
  }
  list() {
    return this.values;
  }
  clear(date) {
    for (let i = this.values.length - 1; i >= 0; --i) {
      if (this.values[i][0] == date) {
        this.values.splice(i, 1);
      }
    }
  }
  total() {
    return this.values[this.amount + this.currency];
  }
}


const art = new Art();

art.add('2017-04-25', 2, 'USD', 'Jogurt');
art.add('2017-04-25', 3, 'USD', 'French fries');
art.add('2017-04-27', 4.75, 'USD', 'Beer');

art.clear('2017-04-27');

console.log(art.list());

console.log(art.total());

total(); should return amount and currency which i've added to art.add. But it output undefined. I've tried to do my best. But all times i have undefined or NaN. Could you please help me?

Upvotes: 2

Views: 49

Answers (1)

Nina Scholz
Nina Scholz

Reputation: 386578

You need to store the values in an array, not a string representation of the data array.

For keeping an amount, you could add it when you insert a new data set or delete the value if you splice an item.

this.totals is implemented as an object with the currency as key and the value as amount.

class Art {
    constructor() {
        this.values = Array();
        this.totals = Object.create(null);
    }
    add(date, amount, currency, product) {
        this.totals[currency] = this.totals[currency] || 0;
        this.totals[currency] += amount;
        this.values.push([date, amount, currency, product]); //.toString());
    }
    list() {
        return this.values;
    }
    clear(date) {
        var amount, currency;
        for (let i = this.values.length - 1; i >= 0; --i) {
            if (this.values[i][0] == date) {
                [, amount, currency] = this.values.splice(i, 1)[0]
                this.totals[currency] -= amount;
            }
        }
    }
    total() {
        return this.totals;
    }
}

const art = new Art();

art.add('2017-04-25', 2, 'USD', 'Jogurt');
art.add('2017-04-25', 3, 'USD', 'French fries');
art.add('2017-04-27', 4.75, 'USD', 'Beer');

art.clear('2017-04-27');

console.log(art.list());

console.log(art.total());

Upvotes: 2

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