Ajax request return ERR_BAD_REQUEST Request failed width status code 400

[valentin6work]

Describe the bug

I have error ERR_BAD_REQUEST Request failed width status code 400 after send ajax post request

To Reproduce

WordPress 5.9.3 send any ajax request to /wp-admin/admin-ajax.php

let form_data = new FormData;
form_data.append('action', 'any_action');
form_data.append('etc..','any value');

axios.post('https://myhost.com/wp-admin/admin-ajax.php', form_data)
.then(function (response)
{
	//--- 
})
.catch(function (error) {
	console.log(error);
});

PHP code in function.php

$action='any_action';
add_action("wp_ajax_nopriv_$action", "$action");
add_action("wp_ajax_$action","$action" );
function any_action)
{
	echo json_encode([
        'post'=>$_POST,
    ]);
    wp_die();
}

Expected behavior

Return result json. Its worked until April 26th!

Environment

• Axios Version [0.27.2]
• WordPress 5.9.3

Additional context/Screenshots

https://prnt.sc/XI2ozoTn9Hgf

[jasonsaayman]

Please check out the docs over here, we have changed the way form data works.

[satanshiro]

Please check out the docs over here, we have changed the way form data works.

fyi the link is for the minified dist instead of docs

[jasonsaayman]

My bad here

[apasov]

I got this 400 error with v0.27.1
After upgrading to v0.27.2 it disappeared.
Looks like it was fixed in #4640

[DigitalBrainJS]

Actually, we did not change anything in working with FormData - we just added alternative shortcut methods and payload serialization to a FormData object when you set the content-type header to multipart/form-data for plain object payload. This is just another shorter way to submit a form without manually creating a FormData object. The old behavior should not be affected, you can still pass the FormData object manually. FormData submits fails were only due to two regression bugs in versions 0.25.0 and 0.27.0.

[anniverskehinde]

🙄**I am Lerner here **

[philBrown]

regression bugs in versions 0.25.0 and 0.27.0

... and 0.27.1