Javascript My Array Push is only getting the last value

Question

I have this for loop that I want to increment the year on every cycle, but I'm only getting the last year all repeating multiple times.

for (let i = 0; i < 2; i++) {
  this.data.year = new Date().getFullYear() + i;
  this.data.noSolar = averageBill * increaseRate;
  this.data.withSolar = (contractAmount * .004) + customerCharge;
  this.data.saving = (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12);
  this.data.check = SREC;
  this.data.total = (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12) + SREC;

  this.dataSource.push(this.data);
}

The Year in this case 2020 is showing twice. I want something like 2019 and 2020. Its like the variable is being reference multiple times.

Well, you are putting the reference to the same object (this.data) multiple times on the array. Maybe, you can create a new object inside the loop (not using this.data for store the values) and then push this new object inside this.dataSource — Shidersz
– Shidersz, Commented May 29, 2019 at 4:03
So you would close the Object after the push or before the push? — Millenial2020
– Millenial2020, Commented May 29, 2019 at 4:06

Hardik Chaudhary · Accepted Answer · 2019-05-29 04:08:41Z

A new object should be created on each iteration. You are referring to the same object every time.

You can do like this,

for (let i = 0; i < 2; i++) {
  this.dataSource.push({
     year : new Date().getFullYear() + i,
     noSolar : averageBill * increaseRate,
     withSolar : (contractAmount * .004) + customerCharge,
     saving : (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12),
     check : SREC,
     total : (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12) + SREC,
  });
}

or do like,

for (let i = 0; i < 2; i++) {
      this.data=new DataSourceObject();
      this.data.year = new Date().getFullYear() + i;
      this.data.noSolar = averageBill * increaseRate;
      this.data.withSolar = (contractAmount * .004) + customerCharge;
      this.data.saving = (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12);
      this.data.check = SREC;
      this.data.total = (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12) + SREC;

      this.dataSource.push(this.data);
    }

random · Accepted Answer · 2019-05-29 04:07:15Z

1

Reference of object is pushed in array. Instead clone or create copy and then push

    const temp = {};
    for (let i = 0; i < 2; i++) {
      this.data.year = new Date().getFullYear() + i;
      this.data.noSolar = averageBill * increaseRate;
      this.data.withSolar = (contractAmount * .004) + customerCharge;
      this.data.saving = (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12);
      this.data.check = SREC;
      this.data.total = (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12) + SREC;
      // this.dataSource.push(...this.data)
      Object.assign(temp, this.data);
      this.dataSource.push(temp);
    };

answered May 29, 2019 at 4:07

random

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1 Comment

Millenial2020 Over a year ago

That code only works if I move the const temp inside the for loop.

Manish Balodia · Accepted Answer · 2019-05-29 04:17:05Z

0

You may try this:-

for (let i = 0; i < 2; i++) {
  this.data.year = new Date().getFullYear() + i;
  this.data.noSolar = averageBill * increaseRate;
  this.data.withSolar = (contractAmount * .004) + customerCharge;
  this.data.saving = (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12);
  this.data.check = SREC;
  this.data.total = (contractAmount * .004 + customerCharge) * 12 - (averageBill * 12) + SREC;

  this.dataSource.push(Object.assign({}, this.data));
}

answered May 29, 2019 at 4:17

Manish Balodia

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