@prestamype/financial-functions/src/_lib/Payment.js

Implementación de funciones financieras

/**
 * Interface -> amort_payment function
 * @param {Number} amount
 * @param {Number} nper
 * @param {Number} commission_rate
 * @param {Number} i_rate
 *
 */

export default class Payment {
	static get_base_amortization(amount, nper, i_rate) {
		return amount / ( ((1+i_rate)**nper - 1)/i_rate )
	}

	static gen_schedule(amount, nper, i_rate, commission_rate) {
		const amort_amount = this.amort_payment(amount, commission_rate)
		const base_amort = this.get_base_amortization(amort_amount, nper, i_rate)
		const total_amount = amount + amount*commission_rate

		let res = Array.from({ length: nper }, () => 0).reduce((c,a,i) => {
			const item = {
				i: c.amount * i_rate,
				amortization: base_amort * (1+i_rate)**i,
			}

			return {
				schedule: [ ...c.schedule, item ],
				amount: c.amount - item.amortization,
			}
		}, { schedule: [], amount: total_amount })

		const payments = res.schedule.map(a => {
			a.fee = a.i + a.amortization
			return a
		})
		payments[payments.length - 1].fee += res.amount

		return {
			payments,
			total_amount,
		}
	}
}