[英]Use Async with .then promise
您好,设置了一个简单的异步函数,并承诺返回,我想使用然后承诺而不是尝试! 但是回来了
等待是保留字
在函数中第二次等待。
我试图放置异步返回承诺数据! 但也没有用
async infiniteNotification(page = 1) {
let page = this.state.page;
console.log("^^^^^", page);
let auth_token = await AsyncStorage.getItem(AUTH_TOKEN);
fetch(`/notifications?page=${page}`, {
method: "GET",
headers: {
Accept: "application/json",
"Content-Type": "application/json",
Access: auth_token
},
params: { page }
})
.then(data => data.json())
.then(data => {
var allData = this.state.notifications.concat(data.notifications);
this.setState({
notifications: allData,
page: this.state.page + 1,
});
let auth_token = await AsyncStorage.getItem(AUTH_TOKEN);
fetch("/notifications/mark_as_read", {
method: "POST",
headers: {
Accept: "application/json",
"Content-Type": "application/json",
Access: auth_token
},
body: JSON.stringify({
notification: {
read: true
}
})
}).then(response => {
this.props.changeNotifications();
});
})
.catch(err => {
console.log(err);
});
}
>等待是保留字(100:25)let auth_token =等待AsyncStorage.getItem(AUTH_TOKEN); ^ fetch(“ / notifications / mark_as_read”,{
您应该重构您的请求方式。 我将具有一个通用功能来处理设置请求和所有操作。
const makeRequest = async (url, options, auth_token) => {
try {
// Default options and request method
if (!options) options = {}
options.method = options.method || 'GET'
// always pass a body through, handle the payload here
if (options.body && (options.method === 'POST' || options.method === 'PUT')) {
options.body = JSON.stringify(options.body)
} else if (options.body) {
url = appendQueryString(url, options.body)
delete options.body
}
// setup headers
if (!options.headers) options.headers = {}
const headers = new Headers()
for(const key of Object.keys(options.headers)) {
headers.append(key, (options.headers as any)[key])
}
if (auth_token) {
headers.append('Access', auth_token)
}
headers.append('Accept', 'application/json')
headers.append('Content-Type', 'application/json')
options.headers = headers
const response = await fetch(url, options as any)
const json = await response.json()
if (!response.ok) {
throw json
}
return json
} catch (e) {
console.error(e)
throw e
}
}
appendQueryString
是用于在网址中获取qs参数的小助手工具
const appendQueryString = (urlPath, params) => {
const searchParams = new URLSearchParams()
for (const key of Object.keys(params)) {
searchParams.append(key, params[key])
}
return `${urlPath}?${searchParams.toString()}`
}
现在,要了解如何更新代码,您会发现事情变得不再那么冗长,而变得更加广泛。
async infiniteNotification(page = 1) {
try {
let auth_token = await AsyncStorage.getItem(AUTH_TOKEN);
const data = await makeRequest(
`/notifications`,
{ body: { page } },
auth_token
)
var allData = this.state.notifications.concat(data.notifications);
this.setState({
notifications: allData,
page: this.state.page + 1,
});
const markedAsReadResponse = makeRequest(
"/notifications/mark_as_read",
{
method: "POST",
body: {
notification: { read: true }
},
auth_token
)
this.props.changeNotifications();
} catch (e) {
// TODO handle your errors
}
}
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