NodeJS - 初探Module (2)

上一篇介紹module.export的使用方式，這一篇介紹它的底層和其它用法

引入整個資料夾

我們可以將一個module拆成數個js檔案，利用一個index.js便可將整個資料夾打包給其它檔案使用

payment/index.js

var creditCard = require('credit_card');
var atmTransfer = require('atm');

module.export = {
	creditCard: creditCard,
	atmTransfer: atmTransfer
};

payment/credit_card.js

var payment = function(price) {
 	console.log('Pay $' + price + 'by credit card");
}

module.export = payment;

payment/atm.js

var payment = function(price) {
	console.log('Pay $' + price + 'by ATM transfer");
}

module.export = payment;

app.js

var payment = require('./payment');

payment.creditCard();
payment.atmTransfer();

上例將payment底下二種不同的付款方式包在index.js檔案給外部使用

利用json檔將設定包裝起來

currency.json

{
	"tw": "NTD",
	"us": "USD"
}

payment/credit_card.js

var currency = require('./currency.json');

var payment = function(price) {
	console.log('Pay $' + price + ' ' + currency.us + 'by credit card");
}

module.export = payment;

用這個方式可將設定值包裝成json檔，增加source code的可讀性

原生module

NodeJS內建許多原生module，這裡是api ducuments。我們以util為例

app.js

var util = require('util');

var price = 100;
var statement = util.format('The price is %s', price);
util.log(statement);

$ 28 Nov 14:54:32 - The price is 100

原生module己提供一些方便的功能，遇到問題時上官網查文件說不定己有解決方案