JavaScript - reading JSON file with require gives different result than fs.readFileSync

user_6182971 0
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I'm getting an issue that makes me think there's something I'm missing about how require works in JavaScript. Basically, if I use require to read a JSON file, I get a different result than using fs.readFileSync.

I start with a JSON file with the following contents:

{"text":"old text"}

I first read the file with require and fs.readFileSync and get the same results for each. I then update the file with fs.writeFileSync and read the file again with require and fs.readFileSync, but I get different results after updating.

It's important to note that I'm requiring the file from inside a function. I would expect this to import the file separately with each function call, but that's apparently not what's happening. Just wondering if someone can explain exactly what's happening.

const fs = require('fs');
const textPath = './test.json';

const oldTextJSON = getText();  // prints as "old text"
const oldTextRead = JSON.parse(fs.readFileSync(textPath)).text;  // prints as "old text"

fs.writeFileSync(textPath, JSON.stringify({
  text: "new text"
}));

const newTextJson = getText();  // prints as "old text"
const newTextRead = JSON.parse(fs.readFileSync(textPath)).text;  // prints as "new text"

function getText() {
  return require(textPath).text;
}
fs node.js require json javascript
1 Answers

Hope this one line explain the characteristics of require.

const path = require("path");


const filepath = path.resolve(textPath);
delete require.cache[filepath];

Basically require reads from the cache no matter how many times you call.

user_27621910
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