Open the Pit! Design and implementation of JavaScript AMD modules

Open a hole and learn to summarize JavaScript's AMD specifications

First write your own simple implementation to put up, and then slowly starting from 0 to explain how AMD, has done its own implementation of an AMD

/*amd*/var DOC = Window.document;var head = Doc.head | | Doc.getelementsbytagname (' head ') [0];var basepath = Getcurrentscript (DOC); basepath = basepath.substring (0, Basepath.lastindexof ('/') +1); noop = function () {};modules = {};function Getemptymodule () {return {deps: [], Offers: [], State:0,factory:noop};}; function Getcurrentscript (DOC) {if (doc.currentscript) {return DOC.currentScript.src;//ff,chrome};var Stack;try { A.B.C ();} catch (e) {stack = E.stack;//Use an error exception to immediately throw a quick get current loaded file path if (!stack && window.opera) {stack = String (e); if (!stack &am p;& window.opera) {stack = (String (e). Match (/of linked script \s+/g) | | []). Join ("");}};}; if (stack) {stack = Stack.split (/[@]/g). Pop ();//Get last line, last space or part after @ stack = stack[0] = = = "("? Stack.slice (1,-1): Stack;return stack.replace (/(: \d+)?: \ d+$/i, ""); Remove the line number with the possible typo character starting position}//ievar nodes = head.getelementsbytagname ("script"); for (var i = 0, node; node = nodes[i++];) {if (node.readystate = = = ' interactive ') {return node.src;};};} functionGetmodulename (URL) {return url.substring (Url.lastindexof ('/') +1, Url.lastindexof ('. js '));} function require (list, factory) {var loaded = 0;var requires = List.length;var args = [];var id = getcurrentscript (DOC); VA R module = Modules[id]?  Modules[id]: Getemptymodule (); module[' factory '] = Factory;modules[id] = module;for (var i=0; i<list.length; i++) {var Depid = basepath+list[i]+ '. js '; Modules[depid] = Modules[depid]? Modules[depid]: Getemptymodule () module[' Deps '].push (depid); if (Modules[depid] && modules[depid].state = = 2 {Modules[depid].offers.push (ID); Loaded++;args.push (modules[depid].exports);//This dependent module is being loaded} else if (modules[depid ] && modules[depid].state = = 1) {Modules[depid].offers.push (ID);//This dependency module has never been loaded} else {//loadjs load module JS, The module JS call Define,define will also require load the dependencies required by this module//thereby function into recursive tracking and load all direct and indirect dependent Modules[depid].offers.push (ID) of this module; Loadjs (depid);};}; if (loaded = = = requires) {module.factory.apply (null, args)};}; function Loadjs (URL) {var module = modules[url];var node = DOC. createelement (' script '); node.onload = Node.onreadystatechange = function () {if (/loaded|complete/i.test ( Node.readystate) | | !node.readystate) {};};   node.src = URL; Head.insertbefore (node, head.firstchild);};  function Findfishedmodules (URL) {var ret = [];var deped = Modules[url];var moduleids = Deped.offers;for (var i = 0; i < Moduleids.length;  i++) {var id = Moduleids[i];var Deps = Modules[id].deps;var flag = False;for (var j = 0; J < Deps.length; J + +) {var dep = Modules[deps[j]];if (Dep.state = = 2 | | deps[j] = = URL) {flag = true;}; if (dep.state! = 2) {flag = False;break;};}; if (flag) {console.info (' module ' +getmodulename (ID) + ' available '); Ret.push (id);};}; return ret;}; function Firefactory (root) {var finshedids = findfishedmodules (root); for (var i = 0; i < finshedids.length; i++) {var m Odule = modules[finshedids[i]];module.factory.apply (null, Getdepsmodules (module.deps)); Firefactory (FinshedIds[i]) ;};}; function Getdepsmodules (deps) {var args = [];for (var i = 0; i < deps.length; i++) {var dep = Deps[i];args.push (modules[dep].exports);}; return args;}; function define (Deps, factory) {var id = getcurrentscript (DOC);//If this module does not rely on installing the module immediately if (deps.length = = 0) {Modules[id]. Exports = factory.apply (null); modules[id].state = 2;//A series of triggering installation Firefactory (ID) from the dependent leaves; return;}; Require (Deps, function () {var _deps = [];for (var i = 0; i < deps.length; i++) {_deps.push (basepath+deps[i]+ '. js ')}; Modules[id].exports = factory.apply (null, Getdepsmodules (_deps)); modules[id].state = 2;});