javascript - fetch - Missing boundary in multipart/form-data POST -

thanks stopping by.

i want send new formdata() body of post request using fetch api

the operation looks this

var formdata = new formdata()  formdata.append('myfile', file, 'somefilename.csv')    fetch('https://api.myapp.com',     {      method: 'post',      headers: {        "content-type": "multipart/form-data"      },      body: formdata    }  )

the problem here boundary,

boundary=----webkitformboundaryyemkndsbkjb7qequ

never makes content-type: header

it should this

content-type:multipart/form-data; boundary=----webkitformboundaryyemkndsbkjb7qequ

when try "same" operation new xmlhttprequest(), so

var request = new xmlhttprequest()  request.open("post", "https://api.mything.com")  request.withcredentials = true  request.send(formdata)

the headers correctly set

content-type:multipart/form-data; boundary=----webkitformboundaryyemkndsbkjb7qequ

so question is,

1. how make fetch behave xmlhttprequest in situation?

2. if not possible, why?

thanks everybody! community more or less reason have professional success.

the solution problem explicitly set content-type undefined browser or whatever client you're using can set , add boundary value in there you. disappointing true.