feat: improve application access and money precision

api/src/common/money.ts

@@ -0,0 +1,36 @@
+import { BadRequestException } from '@nestjs/common';
+
+export const MONEY_UNITS_PER_YUAN = 10_000;
+
+export function moneyToNumber(value: number | bigint | null | undefined) {
+  if (value === null || value === undefined) return 0;
+  const result = typeof value === 'bigint' ? Number(value) : value;
+  if (!Number.isSafeInteger(result)) {
+    throw new RangeError('金额超过 JavaScript 安全整数范围');
+  }
+  return result;
+}
+
+export function moneyUnitsToYuan(value: number | bigint | null | undefined) {
+  return moneyToNumber(value) / MONEY_UNITS_PER_YUAN;
+}
+
+export function moneyUnitsToFixedYuan(value: number | bigint | null | undefined) {
+  return moneyUnitsToYuan(value).toFixed(4);
+}
+
+export function assertMoneyUnits(
+  value: number,
+  label: string,
+  options: { allowNegative?: boolean; allowZero?: boolean } = {},
+) {
+  if (!Number.isSafeInteger(value)) {
+    throw new BadRequestException(`${label}最多支持人民币小数点后 4 位，且不能超过安全金额范围`);
+  }
+  if (!options.allowNegative && value < 0) {
+    throw new BadRequestException(`${label}不能为负数`);
+  }
+  if (options.allowZero === false && value === 0) {
+    throw new BadRequestException(`${label}不能为 0`);
+  }
+}