Oli Sturm
73 lines
2.1 KiB
JavaScript
73 lines
2.1 KiB
JavaScript
import { ok, fail } from '../library/result.js';
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/**
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* @typedef {Object} Account
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* @property {string} id
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* @property {import('./money.js').Money} balance
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*/
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/** @typedef {{ type: 'OpeningBalanceMustBeNonNegative' }} OpeningBalanceMustBeNonNegative */
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/** @typedef {{ type: 'AmountMustBePositive' }} AmountMustBePositive */
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/** @typedef {{ type: 'InsufficientBalance', balance: import('./money.js').Money, amount: import('./money.js').Money }} InsufficientBalance */
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/** @typedef {{ type: 'AccountNotFound', accountId: string }} AccountNotFound */
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/** @typedef {OpeningBalanceMustBeNonNegative | AmountMustBePositive | InsufficientBalance | AccountNotFound} AccountError */
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/**
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* @type {OpeningBalanceMustBeNonNegative}
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*/
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export const openingBalanceMustBeNonNegative = { type: 'OpeningBalanceMustBeNonNegative' };
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/**
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* @type {AmountMustBePositive}
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*/
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export const amountMustBePositive = { type: 'AmountMustBePositive' };
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/**
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* @param {import('./money.js').Money} balance
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* @param {import('./money.js').Money} amount
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* @returns {InsufficientBalance}
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*/
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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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/**
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* @param {string} accountId
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* @returns {AccountNotFound}
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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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/**
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* @param {string} id
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* @param {import('./money.js').Money} openingBalance
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* @returns {import('../library/result.js').Result<Account, AccountError>}
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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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/**
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* @param {Account} account
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* @param {import('./money.js').Money} amount
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* @returns {import('../library/result.js').Result<Account, AccountError>}
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*/
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export const withdraw = (account, amount) => {
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if (amount.amount <= 0) {
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return fail(amountMustBePositive);
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}
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if (account.balance.amount < amount.amount) {
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return fail(insufficientBalance(account.balance, amount));
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}
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return ok({
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...account,
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balance: { amount: account.balance.amount - amount.amount },
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});
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};
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