kmdjs集成uglifyjs2打造极致的编程体验

回顾

上篇文章大概展示了kmdjs0.1.x时期的编程范式：

如下面所示，可以直接依赖注入到function里，

kmdjs.define('main',['util.bom','app.Ball','util.dom.test'], function(bom,Ball,test) {
var ball = new Ball(0, 0, 28, 1, -2, 'kmdjs');
var vp = bom.getViewport();
});


也可以直接在代码里把full namespace加上来调用，如：

kmdjs.define('main',['util.bom','app.Ball','util.dom.test'], function() {
var ball = new app.Ball(0, 0, 28, 1, -2, 'kmdjs');
var vp = util.bom.getViewport();
});


而且，在循环依赖的场景，因为执行顺序的问题，会导致第一种方式注入undefined，所以循环依赖的情况下只能用full namespace的方式来调用。

这种编程体验虽然已经足够好，但是可以更好。怎样才算更好？

1. 不用依赖注入function
2. 不用写full namespace，自动匹配依赖

如下所示：

kmdjs.define('main',['util.bom','app.Ball','util.dom.test'], function() {
var ball = new Ball(0, 0, 28, 1, -2, 'kmdjs');
var vp = bom.getViewport();
});


这就要借助uglifyjs能力，把function的字符串替换成带有namespace就可以实现上面的效果。

uglifyjs依赖分析和代码重构

function fixDeps(fn,deps) {
var U2 = UglifyJS;
//uglify2不支持匿名转ast
var code = fn.toString().replace('function','function ___kmdjs_temp');
var ast = U2.parse(code);
ast.figure_out_scope();
var nodes = []; ast.walk(new U2.TreeWalker(function (node) { if (node instanceof U2.AST_New) {
var ex = node.expression;
var name = ex.name;
isInWindow(name) || isInArray(nodes, node) || isInScopeChainVariables(ex.scope, name) || nodes.push({name:name,node:node});
} if (node instanceof U2.AST_Dot) {
var ex = node.expression;
var name = ex.name;
var scope = ex.scope;
if (scope) {
isInWindow(name) || isInArray(nodes, node) || isInScopeChainVariables(ex.scope, name) || nodes.push({name:name,node:node});
}
} if (node instanceof U2.AST_SymbolRef) {
var name = node.name;
isInWindow(name) || isInArray(nodes, node) || isInScopeChainVariables(node.scope, name) || nodes.push({name:name,node:node});
}
})); var cloneNodes = [].concat(nodes);
//过滤new nodes 中的symbo nodes
for (var i = 0, len = nodes.length; i < len; i++) {
var nodeA = nodes[i].node;
for (var j = 0, cLen = cloneNodes.length; j < cLen; j++) {
var nodeB = cloneNodes[j].node;
if (nodeB.expression === nodeA) {
nodes.splice(i, 1);
i--;
len--;
}
}
} for (var i = nodes.length; --i >= 0;) {
var item = nodes[i],
node=item.node,
name=item.name;
var fullName=getFullName(deps,name);
var replacement;
if (node instanceof U2.AST_New) {
replacement = new U2.AST_New({
expression: new U2.AST_SymbolRef({
name:fullName
}),
args: node.args
});
} else if (node instanceof U2.AST_Dot) {
replacement = new U2.AST_Dot({
expression: new U2.AST_SymbolRef({
name: fullName
}),
property: node.property
});
}else if(node instanceof U2.AST_SymbolRef){
replacement = new U2.AST_SymbolRef({
name: fullName
});
} var start_pos = node.start.pos;
var end_pos = node.end.endpos; code = splice_string(code, start_pos, end_pos, replacement.print_to_string({
beautify: true
}));
}
return code.replace('function ___kmdjs_temp','function');
}function getFullName(deps,name){
var i= 0,
len=deps.length,
matchCount= 0,
result=[]; for(;i<len;i++) {
var fullName = deps[i];
if (fullName.split('.').pop() === name) {
matchCount++;
if (!isInArray(result, fullName)) result.push(fullName);
}
} if(matchCount>1){
throw "the same name conflict: "+result.join(" and ");
} else if(matchCount===1){
return result[0];
}else{
throw ' can not find module ['+name+']';
}
}function splice_string(str, begin, end, replacement) {
return str.substr(0, begin) + replacement + str.substr(end);
}function isInScopeChainVariables(scope, name) {
var vars = scope.variables._values;
if (Object.prototype.hasOwnProperty.call(vars, "$" + name)) {
return true;
} if (scope.parent_scope) {
return isInScopeChainVariables(scope.parent_scope, name);
} return false;
}function isInArray(arr,name){
var i= 0,len=arr.length;
for(;i<len;i++){
if(arr[i]===name){
return true;
}
}
return false;
}function isInWindow(name){
if(name==='this')return true;
return name in window;
}


通过上面的fixDeps，可以对代码就行变换。如：

console.log(fixDeps(function (A) {
var eee = m;
var b = new A();
var b = new B();
var c = new C();
var d = G.a;
},['c.B','AAA.G','SFSF.C','AAAA.m'] ))


输出：

function (A) {
var eee = AAAA.m;
var b = new A();
var b = new c.B();
var c = new SFSF.C();
var d = AAA.G.a;
}


这样，kmdjs在执行模块function的时候，只需要fixDeps加上full namespace就行：

function buildBundler(){
var topNsStr = "";
each(kmdjs.factories, function (item) {
nsToCode(item[0]);
});
topNsStr+= kmdjs.nsList.join('\n') +"\n\n";
each(kmdjs.factories, function (item) {
topNsStr+=item[0]+' = ('+ fixDeps(item[2],item[1])+')();\n\n' ;
});
if(kmdjs.buildEnd) kmdjs.buildEnd(topNsStr);
return topNsStr;
}


build出来的包，当然全都加上了namespace。再也不用区分循环依赖和非循环依赖了~~~

Github

上面的所有代码可以Github上找到：

https://github.com/kmdjs/kmdjs