[英]How to wait for all .then are finished before returning value
我有以下功能
const getQuotes = symbol => {
let quotes = {};
new DeltaRestClient(api_key, api_secret).then(client => {
const linkOptions = createIdentifiers(symbol, false);
Object.entries(linkOptions).forEach(entry => {
client.apis.Products.getTicker({ symbol: entry[1] }).then(response => {
const ticker = JSON.parse(response.data.toString());
quotes[entry[0]] = parseFloat(ticker.result.close);
});
});
});
return quotes;
};
我調用的
const start = async () => {
const quotes = await getQuotes("ABCD");
console.log(quotes);
};
但是由於異步性,getQuotes 在所有 .then 被解析之前返回並返回一個空對象。
如何更改此設置,以便僅在解決所有 .then 時才返回該值?
您也必須在您正在調用的函數中等待:
const getQuotes = async symbol => {
let quotes = {};
const client = await new DeltaRestClient(api_key, api_secret);
const linkOptions = createIdentifiers(symbol, false);
for (const entry of Object.entries(linkOptions)) {
const response = await client.apis.Products.getTicker({ symbol: entry[1] });
const ticker = JSON.parse(response.data.toString());
quotes[entry[0]] = parseFloat(ticker.result.close);
}
return quotes;
};
並相應地調用它:
const start = async () => {
const quotes = await getQuotes("ABCD");
console.log(quotes);
};
一般混合 async/await 和 Promise.then/.catch 會導致容易被誤解的陰暗代碼。
如果您願意,可以通過解構 entry 元素來提高可讀性:
for (const [key, symbol] of Object.entries(linkOptions)) {
const response = await client.apis.Products.getTicker({ symbol, });
const ticker = JSON.parse(response.data.toString());
quotes[key] = parseFloat(ticker.result.close);
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.