Library for loan amortization schedule manipulation

Credit to the original author from with this library was forked: https://github.com/timmson/loan-schedule.js

My main goals with this fork is to reduce dependencies (mainly moment.js and ProdCal), as well as open up customizations to the payment schedule (such as the ability to provide payments manually)

Install

Bun

bun add loan-schedule

Yarn

yarn add loan-schedule

NPM

npm i loan-schedule

Annuity

import { calculateAnnuityLoanSchedule } from 'loan-schedule'

const schedule = calculateAnnuityLoanSchedule(
	{
		amount: 500000,
		rate: 11.5,
		term: 12,
		paymentOnDay: 25,
		issueDate: new Date(2018, 9, 25),
	},
	{ decimalDigit: 2 },
)

Provide payments manually

import { calculateSchedule, generateAnnuityPayments } from 'loan-schedule'

const config = {
	amount: 500000,
	rate: 11.5,
	term: 12,
	paymentOnDay: 25,
	issueDate: new Date(2018, 9, 25),
}
const payments = generateAnnuityPayments(config)
const schedule = calculateSchedule(config, payments)

Annuity loan schedule (payment amount will be calculated)

import { calculateAnnuityLoanSchedule } from 'loan-schedule'

calculateAnnuityLoanSchedule({
	amount: 50000,
	rate: 11.5,
	term: 12,
	paymentOnDay: 25,
	issueDate: new Date(2016, 9, 24),
}).payments.forEach((pay) => {
	console.log(
		pay.paymentDate +
		'\t|\t\t' +
		pay.initialBalance +
		'\t|\t\t' +
		pay.paymentAmount +
		'\t|\t\t' +
		pay.principalAmount +
		'\t|\t\t' +
		pay.interestAmount +
		'\t|\t\t' +
		pay.finalBalance,
	)
})

Annuity loan schedule (payment amount is set)

import { calculateAnnuityLoanSchedule } from 'loan-schedule'

calculateAnnuityLoanSchedule({
	amount: 50000,
	rate: 11.5,
	term: 12,
	paymentAmount: 40000, // Configure your custom payment here
	paymentOnDay: 25,
	issueDate: new Date(2016, 9, 24),
}).payments.forEach((pay) => {
	console.log(
		pay.paymentDate +
		'\t|\t\t' +
		pay.initialBalance +
		'\t|\t\t' +
		pay.paymentAmount +
		'\t|\t\t' +
		pay.principalAmount +
		'\t|\t\t' +
		pay.interestAmount +
		'\t|\t\t' +
		pay.finalBalance,
	)
})

Payment

import { calculateAnnuityPaymentAmount } from 'loan-schedule'

const payment = calculateAnnuityPaymentAmount({
	amount: 110000,
	term: 60,
	rate: 12.9,
})

Other Schedule Types

Bubble Loan

import { calculateBubbleLoanSchedule } from 'loan-schedule'

const schedule = calculateBubbleLoanSchedule({
	amount: 50000,
	rate: 11.5,
	term: 12,
	paymentOnDay: 25,
	issueDate: new Date(2016, 9, 25),
})

Differentiated Loan

import { calculateDifferentiatedLoanSchedule } from 'loan-schedule'

const schedule = calculateDifferentiatedLoanSchedule({
	amount: 50000,
	rate: 11.5,
	term: 12,
	paymentOnDay: 25,
	issueDate: new Date(2016, 9, 25),
})

General Utilities

Interest By Period

import { calculateInterestByPeriod } from 'loan-schedule'

const interest = calculateInterestByPeriod({
	from: new Date(2015, 11, 10),
	to: new Date(2016, 0, 10),
	amount: 1000,
	rate: 16.7,
})

Max Loan Amount

import { calculateMaxLoanAmount } from 'loan-schedule'

const loanAmount = calculateMaxLoanAmount({
	paymentAmount: 2497.21,
	term: 60,
	rate: 12.9,
})