对每个数组项进行api调用

Question

I have an array of object of days, I want to make separate HTTP call for each array item. but the condition is when I get the previous items success response then only I want to make next items API request till I want to wait. suppose I have 5 items in my array so it will make API call immediately. I want that each items API request sequentially. means when my first items API requests response is true then second items API should call.

I have used a for & for each loop and traverse each array item & make HTTP post call but it don't wait for previous requests success response.

 // component call daysArr = [ { day: 'Monday', date: '20-10-2018' }, { day: 'Tuesday', date: '21-10-2018' }, { day: 'Wednesday', date: '22-10-2018' }, { day: 'Thursday', date: '23-10-2018' }, { day: 'Friday', date: '24-10-2018' }, { day: 'Saturday', date: '25-10-2018' }, { day: 'Sunday', date: '26-10-2018' } ] postCall() { let apiUrl = 'https:someurl.com/api/dayspost'; for (let i = 0; i < this.daysArr.length; i++) { // how to check previous request response & make request for next array element this.service.createPost(apiUrl,this.daysArr[i]) .subscribe(response => { console.log('response',response) }) } } //service post call createPost(url, post) { return this.http.post(url,post) .pipe( map(data => { return data; }) ) } 

above is the snippet which displays the API request. but I don't understand how can I check my previous response & then only make new API/post call for new array element.

Thank you.

Answer 1

You can do something like this:

let i = 0;
makeRequest(apiUrl, this.daysArr[i]){
  this.service.createPost(apiUrl,post)
    .subscribe(response => {
       console.log('response',response)
       i++;
       if(i < this.days.length){
          makeRequest(apiUrl, this.daysArr[i])
       }
  })
}

I have no IDE right now to try this, but it should work fine