我有一个简单的模块返回,它使一堆API调用检索数据然后返回它
export default async function getCandles(coins) {
let data = [];
_.forEach(coins, async coin => {
let candles1h = await client.candles({
symbol: coin,
interval: "1h",
limit: 500
});
let candles2h = await client.candles({
symbol: coin,
interval: "2h",
limit: 500
});
let candles4h = await client.candles({
symbol: coin,
interval: "4h",
limit: 500
});
let candles1d = await client.candles({
symbol: coin,
interval: "1d",
limit: 500
});
let candles = {
"1h": candles1h,
"2h": candles2h,
"4h": candles4h,
"1d": candles1d
};
data.push({ coin: candles });
});
return data;
}
我有一个测试文件,它输入数组参数并发送它
async function test() {
let candles = await getCandles(coins);
console.log(candles);
}
当我调用测试函数时,输出只是一个空数组。我在这做错了什么?
问题是getCandles()
无法知道每个批次的异步函数lodash.forEach()
何时创建结果。
一种解决方案可能是使用Promise.all()
调用批量的异步函数。 Promise.all()
是await
able,可以同时发送多个呼叫,而不是按顺序发送。
请参阅下面的粗略示例。
// Get Candles.
const getCandles = async symbol => {
const intervals = ['1h', '2h', '4h', '1d']
const limit = 500
const candles = await Promise.all(intervals.map(async interval => await client.candles({symbol, interval, limit})))
return candles.reduce(async (c, x, i) => {
c[intervals[i]] = x
return c
}, {})
}
// Get Coins.
const getCoins = async symbols => {
const coins = symbols.map(async symbol => ({coin: await getCandles(symbol)}))
return await Promise.all(coins)
}
// Test.
const test = async () => await getCoins(symbols)
我想我会这样做。但我不确定我没试过。
export default async function getCandles(coins) {
return await _.map(coins, async coin => {
let candles1h = await client.candles({
symbol: coin,
interval: "1h",
limit: 500
});
let candles2h = await client.candles({
symbol: coin,
interval: "2h",
limit: 500
});
let candles4h = await client.candles({
symbol: coin,
interval: "4h",
limit: 500
});
let candles1d = await client.candles({
symbol: coin,
interval: "1d",
limit: 500
});
return {
coin: {
"1h": candles1h,
"2h": candles2h,
"4h": candles4h,
"1d": candles1d
}
};
});
}