JavaScript函数默认参数值

Question

I'm trying to set a default value for a function parameter, that will query my server for an initial value.

The end goal is i will be able to click on one of the list items I create to retrieve and create a new list.

<script type="text/javascript">
        $(function getJobs(jobid=0) {
            {#jobid = 0;#}
            console.log("jobid: " + jobid);
            let query = {id: jobid};
            console.log(query);
            $.getJSON("{% url 'website:get-jobs' %}", query, function (data) {
                console.log("getjson");
                $.each(data, function (key, value) {
                    console.log(key + " - " + value);
                    $('#jobs-list').append("<li id='" + key + "'" + "href='#'" + "onclick=getJobs(key)" + ">" + value + "</li>");
                });
            });

        })
</script>

If I manually set jobid to 0(commented out in the code above) everything works perfectly. If i try to set it in the function parameter list i get this in my console.log: jobid: function(e,t){return new w.fn.init(e,t)}

Answer 1

When jQuery calls the callback to $(function(x) { ... }) , the argument is the jQuery object itself, therefore having a default value is never going to be needed

so, you'll want to do this instead

$(function() {
    function getJobs(jobid = 0) {
        console.log("jobid: " + jobid);
        let query = {id: jobid};
        console.log(query);
        $.getJSON("{% url 'website:get-jobs' %}", query, function (data) {
            console.log("getjson");
            $.each(data, function (key, value) {
                console.log(key + " - " + value);
                $('#jobs-list').append("<li id='" + key + "'" + "href='#'" + "onclick=getJobs(key)" + ">" + value + "</li>");
            });
        });
    }
    getJobs();
});

alternatively, using your original code, you could of course test for the case where typeof jobid is a function, and set it to 0 instead ... ie

$(function getJobs(jobid) {
    if (typeof jobid === 'function') {
        jobid = 0;
    }
    console.log("jobid: " + jobid);
    let query = {id: jobid};
    console.log(query);
    $.getJSON("{% url 'website:get-jobs' %}", query, function (data) {
        console.log("getjson");
        $.each(data, function (key, value) {
            console.log(key + " - " + value);
            $('#jobs-list').append("<li id='" + key + "'" + "href='#'" + "onclick=getJobs(key)" + ">" + value + "</li>");
        });
    });
});