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POST Request using fetch API not returning updated data

I'm trying to make a post request with a string. The server is supposed to return the same string, but with an ID added to it to the response.
However, this is the response (Success: ...) that I am getting:
The server is supposed to return the same string as "sent: ..." with ID added to it, but it's just noting that the POST request was successful.
Here's the code that I am using to accomplish this task (vanilla JS):
function saveForm() {
var street = document.getElementById("street").value;
var provinceId = document.getElementById("province").value;
var provinceName = provinces[provinceId]
var cityId = document.getElementById("city").value;
var cityName = cities[cityId].name
var message = document.getElementById("message").value;
var postData = {
Notes: message,
Address: `${provinceName},${cityName},${street}`,
};
// sent: {...}
console.log("sent: ", JSON.stringify(postData));
fetch("https://wavy-media-proxy.wavyapps.com/investors-notebook/inst1/", {
method: "POST",
body: JSON.stringify(postData),
headers: {
"Content-Type": "application/x-www-form-urlencoded",
},
})
.then((data) => {
console.log("Success: ", data);
})
.catch((error) => {
console.error("Error:", error);
});
}
The server has CORS blocked, and I need to change the content-type to "application/x-www-form-urlencoded" as compared to the usual "application/json"
To solve this issue I tried changing the data format to be an object. I also tried to console.log the data in different formats. I checked the network tab, and have not found anything there in the response.
I am out of options but to ask for help. Any ideas would be greatly appreciated.
EDIT: The admin of the server told me he gave me the wrong format for the POST request. It has to include 'entry'.

You should add then((response) => response.json()) after fetch() function to get the response in JSON format, so it should look like:
fetch("https://wavy-media-proxy.wavyapps.com/investors-notebook/inst1/", {
method: "POST",
body: JSON.stringify(postData),
headers: {
"Content-Type": "application/x-www-form-urlencoded",
},
})
.then((response) => response.json())
.then((data) => {
console.log("Success: ", data);
})
.catch((error) => {
console.error("Error:", error);
});
You can read more about fetch API in the official doc: https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#uploading_json_data

Maybe your backend API does not return what you expect? When replacing it with another API and changing the content type to application/json it works:
fetch("https://jsonplaceholder.typicode.com/users/", {
method: "POST",
body: JSON.stringify({Post:123,Data:456}),
headers: {
"Content-Type": "application/json",
},
})
.then((response) => response.json())
.then((data) => {
console.log("Success: ", data);
})
.catch((error) => {
console.error("Error:", error);
});

Getting API authentication key error with PublicAPI

I'm new to the FetchAPAI. For my first API project, I'm currently using the ClimatIQ API and following the steps in their Quickstart guide. Even if I've already signed up and received an authentication key from them, I keep getting the ff error from them:
POST https://beta2.api.climatiq.io/estimate 400
{error: 'invalid_request', message: 'Error parsing the request body.'}
Take note in the guide, the code is in Curl, and I did my best trying to convert that code into a fetchAPI request on JavaScript.
const fetchData = async (url) => {
await fetch(url, {
method: "POST",
headers: { Authorization: "Bearer MY_API_KEY" },
data: {
emission_factor: "electricity-energy_source_grid_mix",
parameters: {
energy: 4200,
energy_unit: "kWh",
},
},
//body: JSON.stringify(data),
})
.then((response) => response.json())
.then((json) => console.log(json))
.catch((err) => console.log(`Here's the error ${err}`));
};
fetchData("https://beta2.api.climatiq.io/estimate");
From time to time, it also shows a "header is not defined" even if I already put in the authentication key they gave me in the "MY_API_KEY" part of my codebase. Is this an error with their server?

try this:
const data = {
emission_factor: "electricity-energy_source_grid_mix",
parameters: {
energy: 4200,
energy_unit: "kWh",
},
};
const fetchData = async(url) => {
await fetch(url, {
method: "POST",
headers: {
Authorization: "Bearer MY_API_KEY",
"Content-Type": "application/json"
},
body: JSON.stringify(data)
})
.then((response) => response.json())
.then((json) => console.log(json))
.catch((err) => console.log(`Here's the error ${err}`));
};
fetchData("https://beta2.api.climatiq.io/estimate");

How to get the response object of an ajax request with laravel?

Guys I'm making a fetch request for laravel without using jquery and I would like to get the return of this request, however when I give a console.log() in the response the console informs undefined.
This is my request:
fetch(action, {
headers: {
"Content-Type": "application/json",
"Accept": "application/json",
"X-Requested-With": "XMLHttpRequest",
"X-CSRF-Token": token
},
method: "post",
credentials: "same-origin",
body: JSON.stringify({
email: email,
password: password
})
})
.then(response => response.json())
.then(data => console.log(data))
.catch(err => console.log(err))
This is my controller that returns the empty field information:
public function login(Request $request)
{
if (in_array('', $request->only('email', 'password'))) {
$json['message'] = "Empty";
return response()->json($json);
}
var_dump($request->all());
}
The request was successful and the browser informs the response message:
Object response message
However console.log(data) returns undefined, how can I return the object that contains the message?
Taking advantage of the question, is this the best way to make this request?
Thank you guys

Spotify Web API Error 400 "Missing Tracks" when removing item from a playlist - Pizzly

I'm trying to remove a song from an authenticated spotify user's playlist and for some reason, I get Error 400 Missing Tracks, even though I know the song is there and the playlist is correct
I am using Pizzly from Bearer to handle the API request
Any idea what could be causing this issue? This is the link to Spotify's API Documentation
This is an example output of JSON.stringify(body)
{"tracks":[{"uri":"spotify:track:2fTdRdN73RgIgcUZN33dvt"}]}
async removeSongsFromPlaylist(context, payload) {
var tracks = payload[0]
var playlistID = payload[1] || context.getters.user.favorites_playlist.id
var authID = context.getters.spotifyAuthID
var endpoint = `/playlists/${playlistID}/tracks`
var uris = tracks.map(track => { return {uri: track.uri}})
var body = {"tracks": uris}
console.log(`URIS:`)
console.log(body);
console.log(`playlist: ${playlistID}`);
return pizzly.integration("spotify").auth(authID).delete(endpoint, {
body: JSON.stringify(body),
headers: { "Content-Type": "application/json" }
})
.then(response => response.json())
.then(responseJSON => {
console.log("song successfully deleted")
console.log(responseJSON)
})
.catch((err) => console.log(err))
},
Update: I did make some progress with a very hacky solution
I took Spotify's cURL example, converted it to fetch with this link and put that inside my function as so:
fetch(`https://api.spotify.com/v1/playlists/${playlistID}/tracks`, {
body: "{\"tracks\":[{\"uri\":\"" + tracks[0].uri + "\"}]}",
headers: {
Accept: "application/json",
Authorization: "Bearer ~accessTokenHiddenForPrivacy~",
"Content-Type": "application/json"
},
method: "DELETE"
})
.then(response => response.json())
Fortunately it worked! The problem is that I tried copy and pasting the body from below into the code above and it still shows "Missing Tracks". I cannot keep this code below without another way of getting the user's access token- which is currently handled by pizzly and the auth id.

How to post file data to Gitlab project using JavaScript fetch [duplicate]

I'm trying to POST a JSON object using fetch.
From what I can understand, I need to attach a stringified object to the body of the request, e.g.:
fetch("/echo/json/",
{
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json'
},
method: "POST",
body: JSON.stringify({a: 1, b: 2})
})
.then(function(res){ console.log(res) })
.catch(function(res){ console.log(res) })
When using jsfiddle's JSON echo I'd expect to see the object I've sent ({a: 1, b: 2}) back, but this does not happen - chrome devtools doesn't even show the JSON as part of the request, which means that it's not being sent.

With ES2017 async/await support, this is how to POST a JSON payload:
(async () => {
const rawResponse = await fetch('https://httpbin.org/post', {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json'
},
body: JSON.stringify({a: 1, b: 'Textual content'})
});
const content = await rawResponse.json();
console.log(content);
})();
Can't use ES2017? See #vp_art's answer using promises
The question however is asking for an issue caused by a long since fixed chrome bug.
Original answer follows.
chrome devtools doesn't even show the JSON as part of the request
This is the real issue here, and it's a bug with chrome devtools, fixed in Chrome 46.
That code works fine - it is POSTing the JSON correctly, it just cannot be seen.
I'd expect to see the object I've sent back
that's not working because that is not the correct format for JSfiddle's echo.
The correct code is:
var payload = {
a: 1,
b: 2
};
var data = new FormData();
data.append( "json", JSON.stringify( payload ) );
fetch("/echo/json/",
{
method: "POST",
body: data
})
.then(function(res){ return res.json(); })
.then(function(data){ alert( JSON.stringify( data ) ) })
For endpoints accepting JSON payloads, the original code is correct

I think your issue is jsfiddle can process form-urlencoded request only. But correct way to make json request is pass correct json as a body:
fetch('https://httpbin.org/post', {
method: 'POST',
headers: {
'Accept': 'application/json, text/plain, */*',
'Content-Type': 'application/json'
},
body: JSON.stringify({a: 7, str: 'Some string: &=&'})
}).then(res => res.json())
.then(res => console.log(res));

From search engines, I ended up on this topic for non-json posting data with fetch, so thought I would add this.
For non-json you don't have to use form data. You can simply set the Content-Type header to application/x-www-form-urlencoded and use a string:
fetch('url here', {
method: 'POST',
headers: {'Content-Type':'application/x-www-form-urlencoded'}, // this line is important, if this content-type is not set it wont work
body: 'foo=bar&blah=1'
});
An alternative way to build that body string, rather then typing it out as I did above, is to use libraries. For instance the stringify function from query-string or qs packages. So using this it would look like:
import queryString from 'query-string'; // import the queryString class
fetch('url here', {
method: 'POST',
headers: {'Content-Type':'application/x-www-form-urlencoded'}, // this line is important, if this content-type is not set it wont work
body: queryString.stringify({for:'bar', blah:1}) //use the stringify object of the queryString class
});

After spending some times, reverse engineering jsFiddle, trying to generate payload - there is an effect.
Please take eye (care) on line return response.json(); where response is not a response - it is promise.
var json = {
json: JSON.stringify({
a: 1,
b: 2
}),
delay: 3
};
fetch('/echo/json/', {
method: 'post',
headers: {
'Accept': 'application/json, text/plain, */*',
'Content-Type': 'application/json'
},
body: 'json=' + encodeURIComponent(JSON.stringify(json.json)) + '&delay=' + json.delay
})
.then(function (response) {
return response.json();
})
.then(function (result) {
alert(result);
})
.catch (function (error) {
console.log('Request failed', error);
});
jsFiddle: http://jsfiddle.net/egxt6cpz/46/ && Firefox > 39 && Chrome > 42

2021 answer: just in case you land here looking for how to make GET and POST Fetch api requests using async/await or promises as compared to axios.
I'm using jsonplaceholder fake API to demonstrate:
Fetch api GET request using async/await:
const asyncGetCall = async () => {
try {
const response = await fetch('https://jsonplaceholder.typicode.com/posts');
const data = await response.json();
// enter you logic when the fetch is successful
console.log(data);
} catch(error) {
// enter your logic for when there is an error (ex. error toast)
console.log(error)
}
}
asyncGetCall()
Fetch api POST request using async/await:
const asyncPostCall = async () => {
try {
const response = await fetch('https://jsonplaceholder.typicode.com/posts', {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify({
// your expected POST request payload goes here
title: "My post title",
body: "My post content."
})
});
const data = await response.json();
// enter you logic when the fetch is successful
console.log(data);
} catch(error) {
// enter your logic for when there is an error (ex. error toast)
console.log(error)
}
}
asyncPostCall()
GET request using Promises:
fetch('https://jsonplaceholder.typicode.com/posts')
.then(res => res.json())
.then(data => {
// enter you logic when the fetch is successful
console.log(data)
})
.catch(error => {
// enter your logic for when there is an error (ex. error toast)
console.log(error)
})
POST request using Promises:
fetch('https://jsonplaceholder.typicode.com/posts', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body: JSON.stringify({
// your expected POST request payload goes here
title: "My post title",
body: "My post content."
})
})
.then(res => res.json())
.then(data => {
// enter you logic when the fetch is successful
console.log(data)
})
.catch(error => {
// enter your logic for when there is an error (ex. error toast)
console.log(error)
})
GET request using Axios:
const axiosGetCall = async () => {
try {
const { data } = await axios.get('https://jsonplaceholder.typicode.com/posts')
// enter you logic when the fetch is successful
console.log(`data: `, data)
} catch (error) {
// enter your logic for when there is an error (ex. error toast)
console.log(`error: `, error)
}
}
axiosGetCall()
POST request using Axios:
const axiosPostCall = async () => {
try {
const { data } = await axios.post('https://jsonplaceholder.typicode.com/posts', {
// your expected POST request payload goes here
title: "My post title",
body: "My post content."
})
// enter you logic when the fetch is successful
console.log(`data: `, data)
} catch (error) {
// enter your logic for when there is an error (ex. error toast)
console.log(`error: `, error)
}
}
axiosPostCall()

I have created a thin wrapper around fetch() with many improvements if you are using a purely json REST API:
// Small library to improve on fetch() usage
const api = function(method, url, data, headers = {}){
return fetch(url, {
method: method.toUpperCase(),
body: JSON.stringify(data), // send it as stringified json
credentials: api.credentials, // to keep the session on the request
headers: Object.assign({}, api.headers, headers) // extend the headers
}).then(res => res.ok ? res.json() : Promise.reject(res));
};
// Defaults that can be globally overwritten
api.credentials = 'include';
api.headers = {
'csrf-token': window.csrf || '', // only if globally set, otherwise ignored
'Accept': 'application/json', // receive json
'Content-Type': 'application/json' // send json
};
// Convenient methods
['get', 'post', 'put', 'delete'].forEach(method => {
api[method] = api.bind(null, method);
});
To use it you have the variable api and 4 methods:
api.get('/todo').then(all => { /* ... */ });
And within an async function:
const all = await api.get('/todo');
// ...
Example with jQuery:
$('.like').on('click', async e => {
const id = 123; // Get it however it is better suited
await api.put(`/like/${id}`, { like: true });
// Whatever:
$(e.target).addClass('active dislike').removeClass('like');
});

Had the same issue - no body was sent from a client to a server.
Adding Content-Type header solved it for me:
var headers = new Headers();
headers.append('Accept', 'application/json'); // This one is enough for GET requests
headers.append('Content-Type', 'application/json'); // This one sends body
return fetch('/some/endpoint', {
method: 'POST',
mode: 'same-origin',
credentials: 'include',
redirect: 'follow',
headers: headers,
body: JSON.stringify({
name: 'John',
surname: 'Doe'
}),
}).then(resp => {
...
}).catch(err => {
...
})

This is related to Content-Type. As you might have noticed from other discussions and answers to this question some people were able to solve it by setting Content-Type: 'application/json'. Unfortunately in my case it didn't work, my POST request was still empty on the server side.
However, if you try with jQuery's $.post() and it's working, the reason is probably because of jQuery using Content-Type: 'x-www-form-urlencoded' instead of application/json.
data = Object.keys(data).map(key => encodeURIComponent(key) + '=' + encodeURIComponent(data[key])).join('&')
fetch('/api/', {
method: 'post',
credentials: "include",
body: data,
headers: {'Content-Type': 'application/x-www-form-urlencoded'}
})

The top answer doesn't work for PHP7, because it has wrong encoding, but I could figure the right encoding out with the other answers. This code also sends authentication cookies, which you probably want when dealing with e.g. PHP forums:
julia = function(juliacode) {
fetch('julia.php', {
method: "POST",
credentials: "include", // send cookies
headers: {
'Accept': 'application/json, text/plain, */*',
//'Content-Type': 'application/json'
"Content-Type": "application/x-www-form-urlencoded; charset=UTF-8" // otherwise $_POST is empty
},
body: "juliacode=" + encodeURIComponent(juliacode)
})
.then(function(response) {
return response.json(); // .text();
})
.then(function(myJson) {
console.log(myJson);
});
}

It might be useful to somebody:
I was having the issue that formdata was not being sent for my request
In my case it was a combination of following headers that were also causing the issue and the wrong Content-Type.
So I was sending these two headers with the request and it wasn't sending the formdata when I removed the headers that worked.
"X-Prototype-Version" : "1.6.1",
"X-Requested-With" : "XMLHttpRequest"
Also as other answers suggest that the Content-Type header needs to be correct.
For my request the correct Content-Type header was:
"Content-Type": "application/x-www-form-urlencoded; charset=UTF-8"
So bottom line if your formdata is not being attached to the Request then it could potentially be your headers. Try bringing your headers to a minimum and then try adding them one by one to see if your problem is resolved.

If your JSON payload contains arrays and nested objects, I would use URLSearchParams and jQuery's param() method.
fetch('/somewhere', {
method: 'POST',
body: new URLSearchParams($.param(payload))
})
To your server, this will look like a standard HTML <form> being POSTed.

You could do it even better with await/async.
The parameters of http request:
const _url = 'https://jsonplaceholder.typicode.com/posts';
let _body = JSON.stringify({
title: 'foo',
body: 'bar',
userId: 1,
});
const _headers = {
'Content-type': 'application/json; charset=UTF-8',
};
const _options = { method: 'POST', headers: _headers, body: _body };
With clean async/await syntax:
const response = await fetch(_url, _options);
if (response.status >= 200 && response.status <= 204) {
let data = await response.json();
console.log(data);
} else {
console.log(`something wrong, the server code: ${response.status}`);
}
With old fashion fetch().then().then():
fetch(_url, _options)
.then((res) => res.json())
.then((json) => console.log(json));

**//POST a request**
const createTodo = async (todo) => {
let options = {
method: "POST",
headers: {
"Content-Type":"application/json",
},
body: JSON.stringify(todo)
}
let p = await fetch("https://jsonplaceholder.typicode.com/posts", options);
let response = await p.json();
return response;
}
**//GET request**
const getTodo = async (id) => {
let response = await fetch('https://jsonplaceholder.typicode.com/posts/' + id);
let r = await response.json();
return r;
}
const mainFunc = async () => {
let todo = {
title: "milan7",
body: "dai7",
userID: 101
}
let todor = await createTodo(todo);
console.log(todor);
console.log(await getTodo(5));
}
mainFunc()

I think that, we don't need parse the JSON object into a string, if the remote server accepts json into they request, just run:
const request = await fetch ('/echo/json', {
headers: {
'Content-type': 'application/json'
},
method: 'POST',
body: { a: 1, b: 2 }
});
Such as the curl request
curl -v -X POST -H 'Content-Type: application/json' -d '#data.json' '/echo/json'
In case to the remote serve not accept a json file as the body, just send a dataForm:
const data = new FormData ();
data.append ('a', 1);
data.append ('b', 2);
const request = await fetch ('/echo/form', {
headers: {
'Content-type': 'application/x-www-form-urlencoded'
},
method: 'POST',
body: data
});
Such as the curl request
curl -v -X POST -H 'Content-type: application/x-www-form-urlencoded' -d '#data.txt' '/echo/form'

You only need to check if response is ok coz the call not returning anything.
var json = {
json: JSON.stringify({
a: 1,
b: 2
}),
delay: 3
};
fetch('/echo/json/', {
method: 'post',
headers: {
'Accept': 'application/json, text/plain, */*',
'Content-Type': 'application/json'
},
body: 'json=' + encodeURIComponent(JSON.stringify(json.json)) + '&delay=' + json.delay
})
.then((response) => {if(response.ok){alert("the call works ok")}})
.catch (function (error) {
console.log('Request failed', error);
});

// extend FormData for direct use of js objects
Object.defineProperties(FormData.prototype, {
load: {
value: function (d) {
for (var v in d) {
this.append(v, typeof d[v] === 'string' ? d[v] : JSON.stringify(d[v]));
}
}
}
})
var F = new FormData;
F.load({A:1,B:2});
fetch('url_target?C=3&D=blabla', {
method: "POST",
body: F
}).then( response_handler )

you can use fill-fetch, which is an extension of fetch. Simply, you can post data as below:
import { fill } from 'fill-fetch';
const fetcher = fill();
fetcher.config.timeout = 3000;
fetcher.config.maxConcurrence = 10;
fetcher.config.baseURL = 'http://www.github.com';
const res = await fetcher.post('/', { a: 1 }, {
headers: {
'bearer': '1234'
}
});