fetch POST is returning HTTP 415, while curl goes on fine and returns result

Question

This is what my code looks like

let body = {
            authCode: "XXXX",
            clientId: "YYYYYY",
            clientSecret: "ZZZZZZ"
        };


        fetch('https://api.myapp.com/oauth/token',{
            method: "POST",
            headers: {
                "Content-Type": "application/json",
                "Accept": "application/json"
            },
            mode: 'no-cors',
            body: body
        }).then(function(response){
            console.log("response: ", response);
        }).catch(function(error){
            console.log("could not get tokens: ", error);
        })

In Chrome, this is what I see

I tried to do this by curl command and this is what it looks like

➜  ~ curl -X POST -H "Content-Type: application/json" -d '{
  "authCode": "XXXX",
  "clientId": "YYYYY",
  "clientSecret": "ZZZZZZZZ"
}' https://api.myapp.com/oauth/token
{"authToken":"e141kjhkwr3432ca9b3d2128385ad91db4cd2:cca6b151-cab4-4de2-81db-9a739a62ae88:23000000"}

What am I doing wrong here?

UPDATE

After changing it to following, the result is still HTTP 415

fetch('https://api.myapp.com/oauth/token',{
            method: "POST",
            headers: {
                "Content-Type": "application/json",
                "Accept": "application/json"
            },
            mode: 'no-cors',
            body: JSON.stringify(body)
        }).then(function(response){
            console.log("response: ", response);
        }).catch(function(error){
            console.log("could not get tokens: ", error);
        })

Interestingly, I realized that I sent the header "Content-Type": "application/json" while what I get back is content-type: text/plain, why that might be happening?

Answer 1

fetch() does not expect a JavaScript object at body. curl command and fetch() pattern are not the same. Use body: JSON.stringify(<javascript plain object>).

Request

Note: The body type can only be a Blob, BufferSource, FormData, URLSearchParams, USVString or ReadableStream type, so for adding a JSON object to the payload you need to stringify that object.

See Fetch with ReadableStream for status of implementation of ReadableStream set as value for body.

Answer 2

you must define Accept and Content-Type headers like that and stringify your data object

const params = {
            headers: {
                'Accept': "application/json, text/plain, */*",
                'Content-Type': "application/json;charset=utf-8"
            },
            body: JSON.stringify(yourObject),
            method: "POST"
        };

fetch(url, params)
        .then(data => { console.log('data', data)})
        .then(res => { console.log('res', res) })
        .catch(error => { console.log('error', error) });