用变化的数据构造多维对象

Question

I have three functions which create three objects, firstPayment , interimPayment and finalPayment

firstPayment will always have data. But interimPayment shouldn't always be used, same finalPayment .

The signifier that interimPayment or finalPayment isn't needed is based on another variable numberOfPayments .

If numberOfPayments === 1 then only firstPayment will have data. If numberOfPayments === 2 then both firstPayment and finalPayment are needed. And finally if numberOfPayments > 2 then all three payment objects are needed.

I'm trying to work out how to add all these objects to another object paymentSchedule based on the numberOfPayments variable.

Here's my start on the code but I'm a bit lost!

  getPaymentSchedule(id) {
    const firstPayment = this.getFirstPayment(id);
    const numberOfPayments = this.getNumberOfPayments(id);

    if (numberOfPayments === 2) {
      const finalPayment = this.getFinalPayment(id);
    } else if (numberOfPayments > 2) {
      const interimPayments = this.getInterimPayments(id);
    }
  }

This is where I'm a bit stuck. I need to add the three objects firstPayment , getInterimPayments and finalPayment in that order, but obviously only if they have been set. I feel like I could do this some quicker way than lots and lots of if statements.

Example of paymentSchedule I am trying to achieve:

{
    firstPayment: {
        label: "foo",
        amount: 123
    },
    interimPayment: {
        label: "foo",
        amount: 123
    },
    finalPayment: {
        label: "foo",
        amount: 123
    },
}

or

{
    firstPayment: {
        label: "foo",
        amount: 123
    },
    finalPayment: {
        label: "foo",
        amount: 123
    },
}

Answer 1

Maybe I'm missing something but is this what you're looking for?

getPaymentSchedule(id) {
    const numberOfPayments = this.getNumberOfPayments(id);
    const schedule = {};
    schedule.firstPayment = this.getFirstPayment(id);

    if (numberOfPayments === 2) {
        schedule.finalPayment = this.getFinalPayment(id);
    } else if (numberOfPayments > 2) {
        schedule.interimPayments = this.getInterimPayments(id);
    }
    return schedule;
}

Answer 2

You could use an array with objects. The array reflects the order and the objects.

[
    {                              // exists always
        name: 'firstPayment',
        label: 'foo',
        amount: 123            
    },
    {                              // numberOfPayments > 2
        name: 'interimPayment',
        label: 'foo',
        amount: 123            
    },
    {                              // numberOfPayments > 1
        name: 'finalPayment',
        label: 'foo',
        amount: 123            
    }
]

To generate, you could use something like this

var schedule = [].concat(
        this.getFirstPayment(id)
        numberOfPayments > 2 ? this.getInterimPayments(id) : [],
        numberOfPayments > 1 ? this.getFinalPayment(id) : []
    );

This generates an array with the wanted payment date.