How download Excel file in Vue.js application correctly?

You need to add the response type as a third argument in your post call

{
    responseType: 'blob'
}

Your final code like that

axios.post(config.backendHost + '/excel', {
    file_name: fileName
}, {
    responseType: 'blob'
}).then((response) => {
    const url = URL.createObjectURL(new Blob([response.data], {
        type: 'application/vnd.ms-excel'
    }))
    const link = document.createElement('a')
    link.href = url
    link.setAttribute('download', fileName)
    document.body.appendChild(link)
    link.click()
});

Or you can use the library FileSaver.js to save your file

import FileSaver from 'file-saver'

axios.post(config.backendHost + '/excel', {
    file_name: fileName
}, {
    responseType: 'blob'
}).then((response) => {

    // response.data is a blob type
    FileSaver.saveAs(response.data, fileName);
});

my case worked:

  axios.get(`/api/v1/companies/${companyId}/export`, {
    responseType: 'blob',
  }).then((response) => {
    const url = URL.createObjectURL(new Blob([response.data]))
    const link = document.createElement('a')
    link.href = url
    link.setAttribute(
      'download',
      `${companyId}-${new Date().toLocaleDateString()}.xlsx`
    )
    document.body.appendChild(link)
    link.click()
  })