如何在for循环内等待响应? [英] How to wait for response inside for loop?
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问题描述
描述:我在for循环中调用了HTTP请求.我想从服务文件中获取响应,然后增加循环.如何等待从服务文件中获取响应,然后执行循环. >
Description : I called an HTTP request inside for loop.I want to get the response from service file then increase loop.How can i wait to get response from service file then execute loop.
for(let i=0;i<final_arr.length;i++)
{
this.user.list_upload(JSON.stringify(ins_arr)).subscribe(data=>{
if(data.hasOwnProperty('STATUS'))
{ if(data.STATUS.toLowerCase()=='success')
{
this.update();
}
else if(data.STATUS.toLowerCase() == 'error')
{
this.user.showToast(data.MESSAGE);
}
}
},err=>{
this.user.showToast("Error occurred in service file");
});
}
请告知
推荐答案
您应使用异步功能.首先将HTTP请求转换为一个Promise,然后在for循环内异步调用该Promise:
You should use an async function. First convert the HTTP request to a promise, then call that promise asynchronously inside the for loop:
asyncReq (){
return new Promise((resolve, reject) => {
this.user.list_upload(JSON.stringify(ins_arr)).subscribe(data=>{
if(data.hasOwnProperty('STATUS')){
if(data.STATUS.toLowerCase()=='success')
{
this.update();
resolve();
}
else if(data.STATUS.toLowerCase() == 'error')
{
this.user.showToast(data.MESSAGE);
reject();
}
}
},err=>{
this.user.showToast("Error occurred in service file");
reject(err);
});
})
}
//Async function where loop progresses only after asyncReq completes
async asyncForFunction () {
for(let i=0; i < final_arr.length; i++){
await this.asyncReq ();
}
}
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