I’m trying to implement filter system in my website. I decided to make it via js. I created fetch function
let filters = document.querySelectorAll('.filters-item');
let pageUrl = wp.page_url;
const postsContainer = document.querySelectorAll('.column.is-half.is-offset-1');
filters.forEach( (item) => {
item.addEventListener('change', (e) =>{
let url = pageUrl + '/wp-admin/admin-ajax.php';
fetch(url, {
method: 'POST',
headers: {
'Content-Type': 'text/html; charset=UTF-8',
},
body: JSON.stringify({
'test': "sampledatatest",
})
}).then( function (response) {
if(response.ok) {
return response.json();
}
return Promise.reject(response);
}).then(function (data) {
console.log(data);
}).catch(function (error) {
console.warn('Error', error);
});
});
});
In my functions.php file I have simple function
add_action('wp_ajax_myfilter', 'misha_filter_function'); // wp_ajax_{ACTION HERE}
add_action('wp_ajax_nopriv_myfilter', 'misha_filter_function');
function misha_filter_function(){
$t = $_POST['test'];
echo $t;
die();
}
When I click on filter
item I’m getting error 400 in my dev console. What am I missing? Is it proper way to pass the data in the form like I did? I don’t want to use jQuery.
1 Answer
Is it proper way to pass the data in the form like I did?
If you mean the body
part (of your fetch()
call), then yes, it is okay.
However,
-
You must send a query named
action
as part of the request (e.g. via the URL likeexample.com/wp-admin/admin-ajax.php?action=test
), so that WordPress knows what AJAX action is it and then execute the callback(s) for that specific action.See here for further information, but in your case, the AJAX action is
myfilter
as inwp_ajax_myfilter
and the callback ismisha_filter_function()
. -
The
Content-Type
header doesn’t match the request body and you should’ve usedapplication/json
instead oftext/html
.
But then, even with the correct request body and headers, the admin-ajax.php
doesn’t actually support JSON request, so if you want to send JSON request, then you should use the WordPress REST API and you’d probably want to add a custom endpoint like my-plugin/v1/myfilter
.
Otherwise, and if you prefer using the admin-ajax.php
, then for example, you can use the FormData()
API in JavaScript to properly build the form data to be sent to admin-ajax.php
:
var formData = new FormData();
formData.append( 'action', 'myfilter' );
formData.append( 'test', 'foo bar baz' );
fetch( url, {
method: 'POST',
body: formData,
} ) // wrapped
.then( res => res.text() )
.then( data => console.log( data ) )
.catch( err => console.log( err ) );