我正在嘗試逐個執行三個獲取請求。每個抓取請求應在完成上一個抓取請求時觸發。以下是我的代碼const chopSegment = (token, frame_tag_url, tag_to_delete_id, chopped_tag_array, tags_for_index_update) => (dispatch) => { let req = fetch(frame_tag_url + tag_to_delete_id + "/", { method: "DELETE", headers: { "Authorization": "Token " + token, "content-type": "application/json" } }) req.then(response => { if (!response.ok) { throw response; } else return response.json(); }).then(response => { return fetch(frame_tag_url, { method: "POST", headers: { "Authorization": "Token " + token, "content-type": "application/json", }, body : JSON.stringify(tags_for_index_update) }).then(response1 => { if (!response1.ok) { throw response1; } return response1.json(); }).then(response => { for(let i = 0; i < chopped_tag_array.length; i++){ return fetch(frame_tag_url, { method: "POST", body: JSON.stringify(chopped_tag_array[i]), headers: { "Authorization": "Token " + token, "content-type": "application/json" } }) .then(response2 => { if (!response2.ok) { throw response2; } return response2.json(); }).then(response2 => { dispatch(chopSegmentSuccess(response2)) }).catch(error => { }) } }).catch(error => { }) }).catch(error => { })}在我的代碼中，只有第一次抓取，即“DELETE”被執行？我做錯了什么？
2 回答
aluckdog
TA貢獻1847條經驗 獲得超7個贊
你不能在循環中做抓取。您將返回完成的第一個抓取。使用 promise 或 await/async 在循環中獲取。如何在循環中返回許多承諾，并等待它們都做其他事情
慕絲7291255
TA貢獻1859條經驗 獲得超6個贊
我寧愿這樣做，創建一個IIFE，并為后續的獲取請求遞歸調用它：
return dispatch =>{
var ctr = 0;
(function myFunc(url, headerObj){
fetch(url, headerObj)
.then(response => {
response.json().then(data=>{
ctr++;
if(ctr ===1 ){ // This could be any condition, say, something on the basis of response; I have taken `ctr` as a condition
myFunc(url, { //You may change this even to different URL, if needed
method: 'POST',
headers: {
'content-type': 'application/json',
'body': ...,
'Authorization':...
}
});
}else if(ctr === 2){
myFunc(url, {
method: 'POST',
headers: {
'content-type': 'application/json',
'body': ...,
'Authorization':...
}
});
}else{
// Any other code
}
})
})
})(url, headerObj);
}
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