invisible-watermark/lib/jsonp.js

watermark auto injector

var count = 0;
function noop() { }
export default function jsonp(url, opts, fn) {
    if ('function' == typeof opts) {
        fn = opts;
        opts = {};
    }
    if (!opts)
        opts = {};
    var prefix = opts.prefix || '__jp';
    // use the callback name that was passed if one was provided.
    // otherwise generate a unique name by incrementing our counter.
    var id = opts.name || prefix + count++;
    var param = opts.param || 'callback';
    var timeout = null != opts.timeout ? opts.timeout : 60000;
    var enc = encodeURIComponent;
    var target = document.getElementsByTagName('script')[0] || document.head;
    var script;
    var timer;
    if (timeout) {
        timer = setTimeout(function () {
            cleanup();
            if (fn)
                fn(new Error('Timeout'));
        }, timeout);
    }
    function cleanup() {
        if (script.parentNode)
            script.parentNode.removeChild(script);
        window[id] = noop;
        if (timer)
            clearTimeout(timer);
    }
    function cancel() {
        if (window[id]) {
            cleanup();
        }
    }
    window[id] = function (data) {
        cleanup();
        if (fn)
            fn(null, data);
    };
    // add qs component
    url += (~url.indexOf('?') ? '&' : '?') + param + '=' + enc(id);
    url = url.replace('?&', '?');
    // create script
    script = document.createElement('script');
    script.src = url;
    target.parentNode.insertBefore(script, target);
    return cancel;
}