Returning coordinates via AJAX-CodePudding

I'm trying to return value via AJAX. Below is the code that I put together based on some examples I found and it seems to work, but I think there's a better way of doing it?

(async () => {
    const url = new URL("/ajax-page", window.location.origin);
            
    const headers = new Headers([
        [
            "Content-Type",
            "application/x-www-form-urlencoded; charset=UTF-8"
        ]
    ]);

    const body = new URLSearchParams([
        ["sl", slug]
    ]);
    
    const res = await fetch(url, {
        method: "POST",
        headers,
        body
    });
                        
    if (res.ok) {                                
        let mkr = await res.text();
            crd = mkr.split("|");  
            lat = crd[0],
            lon = crd[1];

          console.log(lat ' ' lon);
    }
})();

PHP (ajax-page)

// php magic gets values
echo  $mar['lat'].'|'.$mar['lon'];

Do I even need to use (async () => {...})(); anymore?

CodePudding user response：

These lines:

lat = crd[0],
lon = crd[1];

are not variable declarations (because there's no let keyword). It's using the comma operator, so it's equivalent to:

lat = (crd[0], lon = crd[1])

The comma operator returns the value of the second expression, so both lat and lon are being set to crd[1].

The cause of this problem is that you ended the previous two lines with ; rather than ,. The whole declaration should be:

        let mkr = await res.text(),
            crd = mkr.split("|"),
            lat = crd[0],
            lon = crd[1];

If you use your IDE's auto-indent feature it would have shown that this isn't grouped the way you intended.

CodePudding user response：

await can be used only inside an async function. You cannot avoid it. Asynchronous functions implicitly return a promise, so other async functins can await their results.