打字稿和jQuery Ajax

I have the following function:

Updated: added return to $.ajax

searchAjax({url = 'app/php/check.php', data}: {url: any, data: any}): any 
{   
    return $.ajax({
        url: url,
        type: 'post',
        dataType: 'text', 
        data: { data },
        success: function (return_data)
        {   
            return String(return_data);
        },  
        error: function (xhr, status, error) 
        {   
            var err = eval("(" + xhr.responseText + ")");
            console.log(err.Message);
            return err.Message;
        }   
    }); 
}

For now, check.php returns echo 'hi'. Just for testing, I'm trying to console.log the response (in this case return_data). However I get the error EXCEPTION: hi is not defined when I try to console.log it.

Update: Now I get an object with a bunch of stuff and responseText which contains the actual response.

Sounds like your eval isn't getting the text you think it's getting. I believe your result: "echo 'hi'" is stripping the apostrophe so you're actually evaluating "echo hi". This can be an ajax client issue. Or your API is stripping it. Check to see what your browser is receiving from the API.

Also, echo isn't in native javascript

Answering a bit too late. You are not printing the response. You are trying to evaluate the response as a javascript expression. During evaluation, javascript doesn't see 'echo hi' as a valid javascript string and generates the error 'hi is not defined'. And then you are not printing the ajax response itself. You are printing the evaluation result which obviously is a failure in evaluation. You can print the response by writing: console.log(xhr.response);