:hammer: Uplift the function to calculate interest greater than $2000.00 · FagnerMartinsBrack/jack-the-moneylender@408a2cd

GitHub 1 min read

8 Oct '26, 11:12Current

Summary (TL;DR)

This diff shows a code refactoring that extracts a duplicated calculation into a reusable function named calculateInterestForGreaterThan2000. The function computes interest for loan amounts above $2000 by subtracting the threshold from the loan and multiplying by a cents rate. It is then called in three conditional branches handling different loan tiers, replacing inline calculations. The change improves code maintainability and reduces duplication.

`@@ -7,6 +7,12 @@`
`7`	`7`	`assert.strictEqual(actual, expected);`
`8`	`8`	`}`
`9`	`9`
	`10`	`+const calculateInterestForGreaterThan2000 = (loanAmount, endOfFirstRange, centsForSecondRange) => {`
	`11`	`+const dollarsAboveThresholdForGreaterThan2000 = loanAmount.minus(endOfFirstRange);`
	`12`	`+const interestForGreaterThan2000 = centsForSecondRange.multipliedBy(dollarsAboveThresholdForGreaterThan2000);`
	`13`	`+return interestForGreaterThan2000;`
	`14`	`+};`
	`15`	`+`
`10`	`16`	`const interestToPayFor = (loanAmount) => {`
`11`	`17`	`const END_OF_FIRST_RANGE = Money('$2000.00');`
`12`	`18`	`const END_OF_SECOND_RANGE = Money('$5000.00');`
`@@ -18,20 +24,14 @@`
`18`	`24`	`const CENTS_FOR_FOURTH_RANGE = Money('$0.21');`
`19`	`25`
`20`	`26`	`if (loanAmount.greaterThan(END_OF_FIRST_RANGE) && loanAmount.lessThan(Money('$5001.00'))) {`
`21`		`-const calculateInterestForGreaterThan2000 = (loanAmount, endOfFirstRange, centsForSecondRange) => {`
`22`		`-const dollarsAboveThresholdForGreaterThan2000 = loanAmount.minus(endOfFirstRange);`
`23`		`-const interestForGreaterThan2000 = centsForSecondRange.multipliedBy(dollarsAboveThresholdForGreaterThan2000);`
`24`		`-return interestForGreaterThan2000;`
`25`		`-};`
`26`	`27`	`const interestAmount = calculateInterestForGreaterThan2000(loanAmount, END_OF_FIRST_RANGE, CENTS_FOR_SECOND_RANGE);`
`27`	`28`	`return interestAmount;`
`28`	`29`	`}`
`29`	`30`
`30`	`31`	`if (loanAmount.greaterThan(END_OF_SECOND_RANGE) && loanAmount.lessThan(Money('$10001.00'))) {`
`31`	`32`	`let interestAmount = Money('$0.00');`
`32`	`33`
`33`		`-const dollarsAboveThresholdForSecondRange = loanAmount.minus(END_OF_FIRST_RANGE);`
`34`		`-const interestAmountForSecondRange = CENTS_FOR_SECOND_RANGE.multipliedBy(dollarsAboveThresholdForSecondRange);`
	`34`	`+const interestAmountForSecondRange = calculateInterestForGreaterThan2000(loanAmount, END_OF_FIRST_RANGE, CENTS_FOR_SECOND_RANGE);`
`35`	`35`	`interestAmount = interestAmount.plus(interestAmountForSecondRange);`
`36`	`36`
`37`	`37`	`const dollarsAboveThresholdForThirdRange = loanAmount.minus(END_OF_SECOND_RANGE);`
`@@ -44,8 +44,7 @@`
`44`	`44`	`if (loanAmount.greaterThan(END_OF_THIRD_RANGE)) {`
`45`	`45`	`let interestAmount = Money('$0.00');`
`46`	`46`
`47`		`-const dollarsAboveThresholdForSecondRange = loanAmount.minus(END_OF_FIRST_RANGE);`
`48`		`-const interestAmountForSecondRange = CENTS_FOR_SECOND_RANGE.multipliedBy(dollarsAboveThresholdForSecondRange);`
	`47`	`+const interestAmountForSecondRange = calculateInterestForGreaterThan2000(loanAmount, END_OF_FIRST_RANGE, CENTS_FOR_SECOND_RANGE);`
`49`	`48`	`interestAmount = interestAmount.plus(interestAmountForSecondRange);`
`50`	`49`
`51`	`50`	`const dollarsAboveThresholdForThirdRange = loanAmount.minus(END_OF_SECOND_RANGE);`