92304d4fa2
- 首页双向换算：30种主流货币，实时计算，一键互换 - 汇率总览页：一对多查看所有货币换算结果 - 数据源 open.er-api.com，4小时本地缓存 + 失败兜底 - UI 美化：渐变背景、分色货币块、紫色互换按钮 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
131 lines
3.0 KiB
JavaScript
131 lines
3.0 KiB
JavaScript
/**
|
||
* 汇率 API 调用 + 本地缓存
|
||
* 数据源：https://open.er-api.com/v6/latest/{base}
|
||
* 免费，无需 key，每日更新，1500 次/月
|
||
*/
|
||
|
||
const CACHE_KEY = 'exchange_rates';
|
||
const CACHE_TTL = 4 * 60 * 60 * 1000; // 4 小时
|
||
|
||
function getCache() {
|
||
try {
|
||
const data = wx.getStorageSync(CACHE_KEY);
|
||
if (!data) return null;
|
||
return data;
|
||
} catch (e) {
|
||
return null;
|
||
}
|
||
}
|
||
|
||
function setCache(data) {
|
||
try {
|
||
wx.setStorageSync(CACHE_KEY, data);
|
||
} catch (e) {
|
||
console.warn('cache write failed', e);
|
||
}
|
||
}
|
||
|
||
function isCacheValid(cache, base) {
|
||
if (!cache || !cache.rates || !cache.timestamp) return false;
|
||
if (cache.base !== base) return false;
|
||
return Date.now() - cache.timestamp < CACHE_TTL;
|
||
}
|
||
|
||
function fetchRates(base) {
|
||
return new Promise((resolve, reject) => {
|
||
wx.request({
|
||
url: `https://open.er-api.com/v6/latest/${base}`,
|
||
method: 'GET',
|
||
success(res) {
|
||
if (res.statusCode === 200 && res.data && res.data.result === 'success') {
|
||
resolve(res.data.rates);
|
||
} else {
|
||
reject(new Error('API 返回异常'));
|
||
}
|
||
},
|
||
fail(err) {
|
||
reject(err);
|
||
},
|
||
});
|
||
});
|
||
}
|
||
|
||
async function getRates(base) {
|
||
const cache = getCache();
|
||
|
||
if (isCacheValid(cache, base)) {
|
||
return {
|
||
rates: cache.rates,
|
||
updatedAt: cache.updatedAt,
|
||
fromCache: true,
|
||
};
|
||
}
|
||
|
||
try {
|
||
const rates = await fetchRates(base);
|
||
const now = new Date();
|
||
const cacheData = {
|
||
base,
|
||
rates,
|
||
timestamp: now.getTime(),
|
||
updatedAt: formatTime(now),
|
||
};
|
||
setCache(cacheData);
|
||
return {
|
||
rates,
|
||
updatedAt: cacheData.updatedAt,
|
||
fromCache: false,
|
||
};
|
||
} catch (e) {
|
||
// API 失败时用过期缓存兜底
|
||
if (cache && cache.rates) {
|
||
return {
|
||
rates: cache.rates,
|
||
updatedAt: cache.updatedAt + '（缓存）',
|
||
fromCache: true,
|
||
};
|
||
}
|
||
throw e;
|
||
}
|
||
}
|
||
|
||
function convert(amount, fromCode, toCode, rates) {
|
||
if (!rates || !rates[fromCode] || !rates[toCode]) return 0;
|
||
if (fromCode === toCode) return amount;
|
||
return (amount / rates[fromCode]) * rates[toCode];
|
||
}
|
||
|
||
function formatAmount(value, code) {
|
||
// 日元、韩元、越南盾、印尼盾等无小数货币
|
||
const noDecimal = ['JPY', 'KRW', 'VND', 'IDR'];
|
||
if (noDecimal.includes(code)) {
|
||
return Math.round(value).toLocaleString('en-US');
|
||
}
|
||
return Number(value.toFixed(2)).toLocaleString('en-US', {
|
||
minimumFractionDigits: 2,
|
||
maximumFractionDigits: 2,
|
||
});
|
||
}
|
||
|
||
function formatRate(value) {
|
||
if (value >= 100) return value.toFixed(2);
|
||
if (value >= 1) return value.toFixed(4);
|
||
return value.toFixed(6);
|
||
}
|
||
|
||
function formatTime(date) {
|
||
const y = date.getFullYear();
|
||
const m = String(date.getMonth() + 1).padStart(2, '0');
|
||
const d = String(date.getDate()).padStart(2, '0');
|
||
const h = String(date.getHours()).padStart(2, '0');
|
||
const min = String(date.getMinutes()).padStart(2, '0');
|
||
return `${y}-${m}-${d} ${h}:${min}`;
|
||
}
|
||
|
||
module.exports = {
|
||
getRates,
|
||
convert,
|
||
formatAmount,
|
||
formatRate,
|
||
};
|