Import '.json' extension in ES6 Node.js throws an error

Question

We're trying to use the new ways of exporting and importing modules for ES6 with Node.js. It's important for us to get the version number from the package.json file. The following code should do that:

import {name, version} from '../../package.json'

However, on execution the following error is thrown:

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".json" for T:\ICP\package.json imported from T:\ICP\src\controllers\about.js

Is there something we're missing?
Is the extension .json not supported?
Is there another way to retrieve this information using Node.js 13+?

Do you have a json file in that path? Have you tried other ways to import like `import pkg from ('../../package.json')`? — palaѕн, Feb 13 '20 at 11:03

score 113 · Accepted Answer · edited Jan 10 '22 at 21:32

113

According to the Node.js ES Modules docs --experimental-json-modules. is required for importing JSON files.

Include the --experimental-json-modules flag for the module to work.

node --experimental-json-modules about.js

edited Jan 10 '22 at 21:32

Hugovidafe

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answered Feb 13 '20 at 11:08

Idir Hamouch

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Hii Idder, Even I got the same error after adding the flag . yarn run dev --experimental-json-modules that's the script is used to run my project – Hemant Oct 26 '20 at 06:14
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But it's annoying to add that flag every time. Can it be set permanently? – Kokodoko Dec 27 '20 at 13:16
@Kokodoko You can add the flag to one of your startup scripts in package.json. – jewbix.cube Jul 27 '21 at 20:19

Carter Cobb · Answer 2 · 2021-03-05T04:14:28.497

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You can sill import require in an ES6 module for Node.js:

import { createRequire } from "module"; // Bring in the ability to create the 'require' method
const require = createRequire(import.meta.url); // construct the require method
const my_json_file = require("path/to/json/your-json-file.json") // use the require method

edited Mar 05 '21 at 04:14

answered Dec 22 '20 at 03:34

Carter Cobb

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Node.Js v15 lastest give me this error `ReferenceError: require is not defined` – C Alonso C Ortega Jan 31 '21 at 04:26
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@CAlonsoCOrtega We are creating the `require` on line 2 of my answer. If it is undefined, you must have skipped the first few lines. – Carter Cobb Mar 05 '21 at 04:13

score 19 · Answer 3 · answered Apr 17 '21 at 10:22

19

You can use it as in docs node-js as follow:

import { readFile } from 'fs/promises';

const json = JSON.parse(await readFile(new URL('../../package.json', import.meta.url)));

answered Apr 17 '21 at 10:22

DevHub

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If you're doing this on a server... I highly recommend the cleaner `fs-extra`, which promises everything transparently and supports recursive directory copy – Ray Foss May 07 '21 at 18:10
eslint throws error on this as the `await` keyword can only be used within `async` functions – Sina Nov 23 '21 at 12:59

score -2 · Answer 4 · answered Feb 13 '20 at 11:18

-2

yes, there is another way to fetch version, but it is without ES6 module system. Here's a working example: https://codesandbox.io/s/funny-banzai-2xgvf.

answered Feb 13 '20 at 11:18

Anuj Shah

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Require is not `ES6` as you mentioned, so it's not what we're looking for. – DarkLite1 Feb 13 '20 at 11:52

score -6 · Answer 5 · answered Feb 13 '20 at 10:54

-6

try to use

process.env.npm_package_version

this might help you

answered Feb 13 '20 at 10:54

Osama Abdullah

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This will only work if the app is started with `npm`, which is not always the case. – DarkLite1 Feb 13 '20 at 10:55
did you try using fs to load the file ? – Osama Abdullah Feb 13 '20 at 10:58
That seems to be bad practice as it loads the complete file which shows the dependencies and other information that mekes the app vulnerable to attacks. – DarkLite1 Feb 13 '20 at 11:01
This feature will probably be removed... due to the mentioned security concerns, and the lack of support for deno and qbrt – Ray Foss May 07 '21 at 18:13

Import '.json' extension in ES6 Node.js throws an error

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