# 模塊化 ## 模塊化 可以將一些公共的代碼抽離成為一個單獨的 js 文件，作為一個模塊。模塊只有通過[`module.exports`](https://developers.weixin.qq.com/miniprogram/dev/reference/api/module.html)或者`exports`才能對外暴露接口。 注意： - `exports`是[`module.exports`](https://developers.weixin.qq.com/miniprogram/dev/reference/api/module.html)的一個引用，因此在模塊里邊隨意更改`exports`的指向會造成未知的錯誤。所以更推薦開發者采用`module.exports`來暴露模塊接口，除非你已經清晰知道這兩者的關系。 - 小程序目前不支持直接引入`node_modules`, 開發者需要使用到`node_modules`時候建議拷貝出相關的代碼到小程序的目錄中，或者使用小程序支持的[npm](https://developers.weixin.qq.com/miniprogram/dev/devtools/npm.html)功能。 ``` <pre class="calibre13">``` <span class="token6">// common.js</span> <span class="token2">function</span> <span class="token3">sayHello</span><span class="token1">(</span>name<span class="token1">)</span> <span class="token1">{</span> console<span class="token1">.</span><span class="token3">log</span><span class="token1">(</span><span><span class="token4">`Hello </span><span><span class="token1">${</span>name<span class="token1">}</span></span><span class="token4"> !`</span></span><span class="token1">)</span> <span class="token1">}</span> <span class="token2">function</span> <span class="token3">sayGoodbye</span><span class="token1">(</span>name<span class="token1">)</span> <span class="token1">{</span> console<span class="token1">.</span><span class="token3">log</span><span class="token1">(</span><span><span class="token4">`Goodbye </span><span><span class="token1">${</span>name<span class="token1">}</span></span><span class="token4"> !`</span></span><span class="token1">)</span> <span class="token1">}</span> module<span class="token1">.</span>exports<span class="token1">.</span>sayHello <span class="token">=</span> sayHello exports<span class="token1">.</span>sayGoodbye <span class="token">=</span> sayGoodbye ``` ``` 在需要使用這些模塊的文件中，使用`require`將公共代碼引入 ``` <pre class="calibre14">``` <span class="token2">var</span> common <span class="token">=</span> <span class="token3">require</span><span class="token1">(</span><span class="token4">'common.js'</span><span class="token1">)</span> <span class="token3">Page</span><span class="token1">(</span><span class="token1">{</span> helloMINA<span class="token1">:</span> <span class="token2">function</span><span class="token1">(</span><span class="token1">)</span> <span class="token1">{</span> common<span class="token1">.</span><span class="token3">sayHello</span><span class="token1">(</span><span class="token4">'MINA'</span><span class="token1">)</span> <span class="token1">}</span><span class="token1">,</span> goodbyeMINA<span class="token1">:</span> <span class="token2">function</span><span class="token1">(</span><span class="token1">)</span> <span class="token1">{</span> common<span class="token1">.</span><span class="token3">sayGoodbye</span><span class="token1">(</span><span class="token4">'MINA'</span><span class="token1">)</span> <span class="token1">}</span> <span class="token1">}</span><span class="token1">)</span> ``` ```