如何在Node.js中访问导出的“嵌套”函数-TypeError：不是函数

debugcn 发表于 Dev

水瓶座女孩

这是导出的嵌套模块的一种情况：

BaseTutorial.js

// exports module makes the functions public such that they can be accessed in other modules in Node.js.
module.exports.fun_tutorial = function()
{
    console.log("First print from Tutorial.js")                                
}

Extended_NodeTutorial.js

    // `require` is the way to include other modules in

var obj_baseTutorialJS = require('./Base_Tutorial.js');

module.exports.fun_extendedNodeTutorial = function()
{
    console.log("Second print from Extended_NodeTutorial.js")

    this.ss = function fun_nested()         
    {
        console.log("sadasdsa")
        var fun_nested = obj_baseTutorialJS
        fun_nested.fun_tutorial();
    }
}

app.js

var obj_extendedNodeTutorial = require('./Extended_NodeTutorial.js');
console.log(obj_extendedNodeTutorial)

obj_extendedNodeTutorial.fun_extendedNodeTutorial();
obj_extendedNodeTutorial.fun_extendedNodeTutorial.fun_nested();

执行后发生错误`node app.js`：

{ fun_extendedNodeTutorial: [Function] }
Second print from Extended_NodeTutorial.js
/home/***/Documents/home_notes/MEAN/app.js:7
obj_extendedNodeTutorial.fun_extendedNodeTutorial.fun_nested();
                                                  ^

TypeError: obj_extendedNodeTutorial.fun_extendedNodeTutorial.fun_nested is not a function
    at Object.<anonymous> (/home/***/Documents/home_notes/MEAN/app.js:7:51)
    at Module._compile (module.js:569:30)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
    at Function.Module.runMain (module.js:605:10)
    at startup (bootstrap_node.js:158:16)
    at bootstrap_node.js:575:3

vatz88

我不知道您要达到什么目的，但是有多种方法可以解决此问题。

1）您可以返回嵌套函数。

BaseTutorial.js

module.exports.fun_tutorial = function()
{
    console.log("First print from Tutorial.js")                                
}

Extended_NodeTutorial.js

var obj_baseTutorialJS = require('./Base_Tutorial.js');

module.exports.fun_extendedNodeTutorial = function()
{
    console.log("Second print from Extended_NodeTutorial.js");

    return fun_nested()
    {
        console.log("sadasdsa");
        const fun_tutorial = obj_baseTutorialJS.fun_tutorial;
        fun_tutorial();
    }
}

app.js

var obj_extendedNodeTutorial = require('./Extended_NodeTutorial.js');
console.log(obj_extendedNodeTutorial)

const fun_nested = obj_extendedNodeTutorial.fun_extendedNodeTutorial();
fun_nested(); // adasdsa

2）您可以创建从导出的函数的实例`Extended_NodeTutorial.js`。我看到您正在尝试使用`this.ss`。要达到类似的目的，您必须使用`new`关键字。

BaseTutorial.js

module.exports.fun_tutorial = function()
{
    console.log("First print from Tutorial.js")                                
}

Extended_NodeTutorial.js

var obj_baseTutorialJS = require('./Base_Tutorial.js');

module.exports.fun_extendedNodeTutorial = function()
{
    console.log("Second print from Extended_NodeTutorial.js")

    this.fun_nested = function()
    {
        console.log("sadasdsa");
        const fun_nested = obj_baseTutorialJS.fun_tutorial;
        fun_tutorial();
    }
}

app.js

var obj_extendedNodeTutorial = require('./Extended_NodeTutorial.js');
console.log(obj_extendedNodeTutorial)

const fun_extendedNodeTutorial = new obj_extendedNodeTutorial.fun_extendedNodeTutorial(); // Second print from Extended_NodeTutorial.js
fun_extendedNodeTutorial.fun_nested(); // sadasdsa

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