skylark-utils/src/scripter.js

An Elegant HTML5 JavaScript Library.

define([
    "./skylark",
    "./langx",
    "./noder",
    "./finder"
], function(skylark, langx, noder, finder) {

    var head = document.getElementsByTagName('head')[0],
        scriptsByUrl = {},
        scriptElementsById = {},
        count = 0;

    function scripter() {
        return scripter;
    }

    langx.mixin(scripter, {

        loadJavaScript: function(url, loadedCallback, errorCallback) {
            var script = scriptsByUrl[url];
            if (!script) {
                script = scriptsByUrl[url] = {
                    state: 0, //0:unload,1:loaded,-1:loaderror
                    loadedCallbacks: [],
                    errorCallbacks: []
                }
            }

            script.loadedCallbacks.push(loadedCallback);
            script.errorCallbacks.push(errorCallback);

            if (script.state === 1) {
                script.node.onload();
            } else if (script.state === -1) {
                script.node.onerror();
            } else {
                var node = script.node = document.createElement("script"),
                    id = script.id = (count++);

                node.type = "text/javascript";
                node.async = false;
                node.defer = false;
                startTime = new Date().getTime();
                head.appendChild(node);

                node.onload = function() {
                        script.state = 1;

                        var callbacks = script.loadedCallbacks,
                            i = callbacks.length;

                        while (i--) {
                            callbacks[i]();
                        }
                        script.loadedCallbacks = [];
                        script.errorCallbacks = [];
                    },
                    node.onerror = function() {
                        script.state = -1;
                        var callbacks = script.errorCallbacks,
                            i = callbacks.length;

                        while (i--) {
                            callbacks[i]();
                        }
                        script.loadedCallbacks = [];
                        script.errorCallbacks = [];
                    };
                node.src = url;

                scriptElementsById[id] = node;
            }
            return script.id;
        },

        deleteJavaScript: function(id) {
            var node = scriptElementsById[id];
            if (node) {
                var url = node.src;
                noder.remove(node);
                delete scriptElementsById[id];
                delete scriptsByUrl[url];
            }
        }
    });

    return skylark.scripter = scripter;
});