如何在 Node.js 中创建模块?
模块是一个单独的逻辑文件中的 JavaScript 代码的集合,可以根据它们的相关功能在外部应用程序中使用。模块很受欢迎,因为它们易于使用且可重用。
要在 Node.js 中创建一个模块,需要导出关键字。这个关键字告诉 Node.js 这个函数可以在模块外使用。
语法:
exports.function_name = function(arg1, arg2, ....argN) {
// function body
};
自定义节点模块示例:
-
创建要导出的文件
```js // File name: calc.js
exports.add = function (x, y) { return x + y; };
exports.sub = function (x, y) { return x - y; };
exports.mult = function (x, y) { return x * y; };
exports.div = function (x, y) { return x / y; }; ```
-
使用‘要求’关键字导入文件
```js // File name: App.js var calculator = require('./calc');
var x = 50, y = 20;
console.log("Addition of 50 and 20 is " + calculator.add(x, y));
console.log("Subtraction of 50 and 20 is " + calculator.sub(x, y));
console.log("Multiplication of 50 and 20 is " + calculator.mult(x, y));
console.log("Division of 50 and 20 is " + calculator.div(x, y)); ```
-
输出:
```js Addition of 50 and 20 is 70 Subtraction of 50 and 20 is 30 Multiplication of 50 and 20 is 1000 Division of 50 and 20 is 2.5
```
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