@mr-krabs/money
v1.0.1
Published
Mr. Crabs Money Utility
Readme
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@**@ Mr Krabs Money Class Documentation
"MONEY! MONEY! MONEY!" - Mr. Krabs 🦀
A type-safe class for handling monetary values in TypeScript, preventing floating-point precision errors by storing amounts as cents in BigInt.
Key Features
- Precise decimal calculations
- Safe arithmetic operations
- Immutable value semantics
- Formatting utilities
- Comparison methods
Creating Money Objects
static fromDollars(amount: number): Money
Creates a Money instance from a dollar amount.
// Mr. Krabs calculating his daily revenue
const dailyRevenue = Money.fromDollars(496.99);
console.log(dailyRevenue.format()); // "496.99"static fromCents(cents: number | bigint): Money
Creates a Money instance from a cent amount.
// Mr. Krabs counting every last cent from the register
const penniesFound = Money.fromCents(4242);
console.log(penniesFound.format()); // "42.42"static zero(): Money
Creates a Money instance with zero value.
// Starting Mr. Krabs' daily profits counter
let dailyProfits = Money.zero();Operations
add(other: Money | number): Money
Adds another monetary value.
// Mr. Krabs calculating Krabby Patty sales
const pattyPrice = Money.fromDollars(5.99);
let totalSales = Money.zero();
// After selling 3 Krabby Patties
totalSales.add(pattyPrice).add(pattyPrice).add(pattyPrice);
console.log(totalSales.format()); // "17.97"subtract(other: Money | number): Money
Subtracts another monetary value.
// Mr. Krabs calculating profits after paying SpongeBob
const revenue = Money.fromDollars(1000);
const spongebobSalary = Money.fromDollars(7.25);
const profit = revenue.clone().subtract(spongebobSalary);
console.log(profit.format()); // "992.75"multiply(factor: number): Money
Multiplies the amount by a factor.
// Mr. Krabs calculating a week's worth of profits
const dailyProfit = Money.fromDollars(100);
const weeklyProfit = dailyProfit.clone().multiply(7);
console.log(weeklyProfit.format()); // "700.00"Getters and Formatting
dollars: number
Gets the amount in dollars as a number.
const safe = Money.fromDollars(10000);
console.log(`Mr. Krabs has $${safe.dollars} in his safe!`);asCents: bigint
Gets the raw cent amount as a BigInt.
const penny = Money.fromCents(1);
console.log(`A penny is worth ${penny.asCents} cent`);format(): string
Formats the amount as a string with 2 decimal places.
// Mr. Krabs writing his ledger
const tip = Money.fromDollars(3.50);
console.log(`Tip received: $${tip.format()}`);Comparison Methods
equals(other: Money): boolean
Checks if two monetary values are equal.
// Mr. Krabs checking if he got exact change
const price = Money.fromDollars(9.99);
const paid = Money.fromDollars(10.00);
console.log(price.equals(paid)); // falsegreaterThan(other: Money): boolean
Checks if this amount is greater than another.
// Mr. Krabs comparing today's profits with yesterday's
const today = Money.fromDollars(531.42);
const yesterday = Money.fromDollars(489.99);
if (today.greaterThan(yesterday)) {
console.log("Arg arg arg! Better than yesterday!");
}lessThan(other: Money): boolean
Checks if this amount is less than another.
// Mr. Krabs checking if he's losing money
const expenses = Money.fromDollars(100);
const income = Money.fromDollars(95);
if (income.lessThan(expenses)) {
console.log("We're losing money! SPONGEBOB!");
}State Checking
isZero(): boolean
Checks if the amount is zero.
// Mr. Krabs checking the register
const register = Money.zero();
if (register.isZero()) {
console.log("EMPTY REGISTER! WHO TOOK ME MONEY?!");
}isNegative(): boolean
Checks if the amount is negative.
// Mr. Krabs checking his bottom line
const balance = Money.fromDollars(-10);
if (balance.isNegative()) {
console.log("We're in the red! Cut everyone's salary!");
}isPositive(): boolean
Checks if the amount is positive.
// Mr. Krabs checking if there's any profit
const profit = Money.fromDollars(0.01);
if (profit.isPositive()) {
console.log("At least we made something! Arg arg arg!");
}Best Practices
- Always use
clone()when you need to perform calculations on a copy - Use
fromDollars()for user input andfromCents()for internal calculations - Always compare Money objects using the provided comparison methods
- Use
format()when displaying values to users