Oli Sturm
38 lines
1.1 KiB
JavaScript
38 lines
1.1 KiB
JavaScript
import { ok, fail } from '../library/result.js';
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import { match, when, any } from '../library/patterns.js';
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export const openingBalanceMustBeNonNegative = { type: 'OpeningBalanceMustBeNonNegative' };
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export const amountMustBePositive = { type: 'AmountMustBePositive' };
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export const insufficientBalance = (balance, amount) => ({
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type: 'InsufficientBalance',
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balance,
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amount,
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});
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export const accountNotFound = (accountId) => ({
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type: 'AccountNotFound',
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accountId,
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});
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export const openAccount = (id, openingBalance) =>
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openingBalance.amount < 0
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? fail(openingBalanceMustBeNonNegative)
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: ok({ id, balance: openingBalance });
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export const withdraw = (account, amount) =>
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match(
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when(({ amount: a }) => a.amount <= 0, () => fail(amountMustBePositive)),
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when(
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({ account: acc, amount: amt }) => acc.balance.amount < amt.amount,
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({ account: acc, amount: amt }) => fail(insufficientBalance(acc.balance, amt))
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),
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when(any, ({ account: acc, amount: amt }) =>
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ok({
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...acc,
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balance: { amount: acc.balance.amount - amt.amount },
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})
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)
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)({ account, amount });
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