fs vs require JSON

Question

I'll start of with saying I'm new to NodeJS but i've been developing in PHP for a number of years (doesn't mean much I know).

I started tinkering with Node recently and discovered something strange I hope someone can help with

I have a file call local.js this pulls in a .JSON file that is used to setting such as oAuth keys and the like.

The initial way I pulled this file in was like:

var fs = require('fs')
var settings = fs.readFileSync('./config/settings.json', 'utf8')

What I found was that I wouldn't be able to read a value from the JSON in settings via settings.key this would give me undefined

Testing out another method below

var settings = require('./config/settings.json')

Allows me to read the value from the JSON via settings.key

I was wonder why this is the case?

Answer 1

fs.readFileSync() just reads the data contained in the file, but it doesn't parse it.

For that, you need an additional step:

var settings = JSON.parse( fs.readFileSync('./config/settings.json', 'utf8') );

Using require() will parse the data automatically.

Answer 2

Function fs.readFileSync() reads only the contents of file as a string.

While require() will read the contents of file as well as parse it using JSON.parse() function so you will get a json object in return.

Its better to use require() if you are not modifying the json file in between your execution.