rely.js

(function (global) {
    if (global.relyjs) {
        return
    }

    var relyjs = global.relyjs = {
        version: "1.2.0"
    }
    var doc = document;
    var event = relyjs.event = {};
    var cache = relyjs.cache = {};
    var data = relyjs.data = {
        "filename": 'rely.js',
        'basepath': ''
    };
    function getBasePath() {
        var scripts = document.scripts || document.getElementsByTagName("script");
        for (var i = 0, l = scripts.length; i < l; i++) {
            var src = scripts[i].src;
            cache[src] = true;
            if (src.indexOf(data['filename']) > -1) {
                data.basepath = src.slice(0, src.lastIndexOf('/') + 1);
            }
        }
    }
    getBasePath();

    function request(url, callback, charset, crossorigin) {
        if (cache[normalize(url, data.basepath)]) {
            return;
        }
        var node = doc.createElement("script");
        var head = doc.head || doc.getElementsByTagName("head")[0] || doc.documentElement;
        var baseElement = head.getElementsByTagName("base")[0];
        if (charset) {
            node.charset = charset
        }
    
        if (!isType("Undefined",crossorigin)) {
            node.setAttribute("crossorigin", crossorigin)
        }
        node.async = true
        node.src = normalize(url, data.basepath)
        currentlyAddingScript = node;
        baseElement ? head.insertBefore(node, baseElement) : head.appendChild(node);
        cache[node.src] = true;
    }
    relyjs.request = request;

    var config = relyjs.config = function (configData) {
        for (var key in configData) {
            var currConfig = configData[key];
            var bakConfig = data[key];
            if (bakConfig && isObject(bakConfig)) {
                for (var k in currConfig) {
                    bakConfig[k] = currConfig[k]
                }
            } else {
                if (isType("Array",bakConfig)) {
                    currConfig = bakConfig.concat(currConfig)
                } else if (key === "basepath") {
                    if (currConfig.slice(-1) !== "/") {
                        currConfig += "/"
                    }
                    currConfig = addBase(currConfig)
                }
                data[key] = currConfig;
            }
        }
        return relyjs
    }
    /**
     * 断言是不是某个类型
     * @param {String} type 
     * @param {*} obj 
     */
    function isType(type, obj) {
        return Object.prototype.toString.call(obj) === "[object " + type + "]"
    }

    /**
     * 判断路径是不是绝对路径
     * @param {String} path
     * @returns {String} realpath
     */
    function addBase(path) {
        if (/^([a-z]{3,5}:\/\/\S*?\/|\/)/.test(path)) {
            return path;
        } else {
            return normalize(name, data.basepath)
        }
    }

    /**
     * 根据依赖模块的相对路径和basePath合成真实路径
     * @param {String} name 依赖的模块可以是相对路径或者在alias配置中的别名
     * @param {String} basePath 
     * @returns {String} realPath 合成后的真实路径
     */

    function normalize(name, basePath) {
        if (isType('String', name) && isType('String', basePath)) {
            var namepart, backSize = 0, basepart, domain, realSize;
            switch (name.slice(0, 2)) {
                case '..':
                    namepart = name.split('../');
                    backSize = namepart.length - 1;
                    break
                case './':
                    if (name.indexOf("../") > -1) {
                        return normalize(name.slice(2), basePath);
                    } else {
                        namepart = name.split('./');
                    }
                    break
                default:
                    name = data.alias[name]
                    return normalize(name, basePath);
            }
            domain = /^[a-z]{3,5}:\/\/\S*?\//.exec(basePath)[0];
            basePath = basePath.replace(domain, "");
            basepart = basePath.split("/");
            realSize = basepart.length - 1 - backSize;
            if (realSize < 1) {
                throw new Error("path synthesis failed Please check if the parameters are correct");
            }
            return (realSize ? domain + basepart.slice(0, realSize).join("/") : domain.slice(0, -1)) + (namepart.length != 1 ? '/' + namepart[namepart.length - 1] : namepart[0].slice(1));

        }
        throw new Error("args [name,basename] Must be a string")
    }

    function define(lib, callback) {
        if(isType('Array',lib) && isType("Function",callback)){
            lib.forEach(function (item) {
                request(item)
            });
            doc.onreadystatechange = function(){
                if(doc.readyState === 'complete'){
                    callback();
                }
            }
        }else if(isType('Function',lib) && isType("Undefined",callback)){
            doc.onreadystatechange = function(){
                if(doc.readyState === 'complete'){
                    lib();
                }
            }
        }
    }

    global.define = relyjs.define = define;
}(this))