深度剖析典型函数内部作用域链的动态变化

function factory() {
     var name = 'laruence';
     var intro = function(){
          alert('I am ' + name);
     }
     return intro;
}
 
function app(para){
     var name = para;
     var func = factory();
     func();
}
 
app('eve');

contentStack = {

    globalContext
}

globalContext = {

    globalariableObject : [factory,app],

    globalScopeChain : globalariableObject

}

app.[[Scope]] = globalScopeChain;

----------------------------------------------

contentStack = {

    appContext,
    globalContext
}

appContext = {

    appariableObject : [arguments,para,name,func,factory,app],

    appScopeChain : [appariableObject, app.[[Scope]]]

}

factory.[[Scope]] = appScopeChain;

-----------------------------------------------

contentStack = {

    factoryContext,

    appContext,

    globalContext

}

factoryContext  = {

   factoryariableObject : [arguments, name, intro,factory],

   factoryScopeChain : [factoryariableObject, factoryScope]

}

intro.[[Scope]] = factoryScopeChain;

------------------------------------------------

contentStack = {
    introContext,

    factoryContext,

    appContext,

    globalContext

}

introContext = {

    introariableObject = [arguments,name,intro],

    introScopeChain = [introariableObject, intro.[[Scope]]]

}

 

因此最终的执行结果是intro可以访问到的name，也即laruence。