本文翻译自：Using Node.JS, how do I read a JSON file into (server) memory?
Background背景
I am doing some experimentation with Node.js and would like to read a JSON object, either from a text file or a .js file (which is better??) into memory so that I can access that object quickly from code.我正在对Node.js进行一些实验，并希望从文本文件或.js文件（更好的??）中读取JSON对象到内存中，以便我可以从代码中快速访问该对象。I realize that there are things like Mongo, Alfred, etc out there, but that is not what I need right now.我意识到那里有Mongo，Alfred等东西，但这不是我现在所需要的。
Question题
How do I read a JSON object out of a text or js file and into server memory using JavaScript/Node?如何使用JavaScript / Node从文本或js文件和服务器内存中读取JSON对象？
#1楼
参考：/question/g0Jv/使用Node-JS-如何将JSON文件读入-服务器-内存
#2楼
Sync:同步：
var fs = require('fs');var obj = JSON.parse(fs.readFileSync('file', 'utf8'));
Async:异步：
var fs = require('fs');var obj;fs.readFile('file', 'utf8', function (err, data) {if (err) throw err;obj = JSON.parse(data);});
#3楼
Asynchronous is there for a reason!异步是有原因的！Throws stone at @mihai在@mihai扔石头
Otherwise, here is the code he used with the asynchronous version:否则，这是他用于异步版本的代码：
// Declare variablesvar fs = require('fs'),obj// Read the file and send to the callbackfs.readFile('path/to/file', handleFile)// Write the callback functionfunction handleFile(err, data) {if (err) throw errobj = JSON.parse(data)// You can now play with your datas}
#4楼
The easiest way I have found to do this is to just userequireand the path to your JSON file.我发现这样做的最简单方法是使用require和JSON文件的路径。
For example, suppose you have the following JSON file.例如，假设您有以下JSON文件。
test.jsontest.json
{"firstName": "Joe","lastName": "Smith"}
You can then easily load this in your node.js application usingrequire然后，您可以使用require在node.js应用程序中轻松加载它
var config = require('./test.json');console.log(config.firstName + ' ' + config.lastName);
#5楼
/dist/latest-v6.x/docs/api/fs.html#fs_fs_readfile_file_options_callback/dist/latest-v6.x/docs/api/fs.html#fs_fs_readfile_file_options_callback
var fs = require('fs'); fs.readFile('/etc/passwd', (err, data) => {if (err) throw err;console.log(data);}); // optionsfs.readFile('/etc/passwd', 'utf8', callback);
/dist/latest-v6.x/docs/api/fs.html#fs_fs_readfilesync_file_options/dist/latest-v6.x/docs/api/fs.html#fs_fs_readfilesync_file_options
You can find all usage of Node.js at the File System docs!您可以在文件系统文档中找到Node.js的所有用法！
hope this help for you!希望对你有所帮助！
#6楼
In Node 8 you can use the built-inutil.promisify()to asynchronously read a file like this在Node 8中，您可以使用内置的util.promisify()来异步读取这样的文件
const {promisify} = require('util')const fs = require('fs')const readFileAsync = promisify(fs.readFile)readFileAsync(`${__dirname}/my.json`, {encoding: 'utf8'}).then(contents => {const obj = JSON.parse(contents)console.log(obj)}).catch(error => {throw error})
