Read app.json (or exp.json) programmatically

Question

Is there a way to read the contents of app.json programmatically from within you app, so you could for example get the current version number and show it within an About screen?

brentvatne · Accepted Answer · 2020-05-09T18:26:27.997

66

You can access this through Constants.manifest. This includes your app.json config without any of the potentially sensitive information such as API secret keys.

import Constants from 'expo-constants';
Constants.manifest.version

edited May 09 '20 at 18:26

answered Jul 23 '17 at 21:10

brentvatne

7,603
4
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55

1

@brentvatne, how can we access version in expo SDK 33, coz I am facing the issue while getting the version. – Arvindlal Jaiswal Jul 12 '19 at 10:44
how would you put google map api key in app.js ? I tried to add a googmapkey, it said invalid key – angry kiwi Jul 17 '19 at 20:25
@Milean - I updated the code to switch over to using expo-constants – brentvatne May 09 '20 at 18:26
3

This does not work in SDK 46. – phatmann Aug 17 '22 at 15:54

score 5 · Answer 2 · answered May 09 '20 at 15:42

5

For Expo SDK 35, I did this:

expo install expo-constants

in your .js:

import Constants from "expo-constants";

<Text> {Constants.manifest.description} </Text>

answered May 09 '20 at 15:42

Milean

878
9
16

score 4 · Answer 3 · answered Oct 08 '22 at 22:17

4

As of Expo SDK 46, use Constants.expoConfig. Source: https://github.com/expo/expo/discussions/17176

answered Oct 08 '22 at 22:17

nvbach91

166
8

score 3 · Answer 4 · answered Sep 25 '19 at 07:14

3

For expo SDK 33 use:

 import Constants from "expo-constants";
 {`v${Constants.manifest.version}`}

answered Sep 25 '19 at 07:14

Arvindlal Jaiswal

257
2
10

score 3 · Answer 5 · answered Sep 24 '21 at 01:28

3

npm:

npm install expo-constants

OR

expo:

expo install expo-constants

About.js

import Constants from "expo-constants";

<Text>Version {Constants.manifest.version} </Text>

answered Sep 24 '21 at 01:28

Jay

308
2
10

score 1 · Answer 6 · answered Feb 25 '20 at 08:16

1

Newer versions of expo (I'm on 36) now import the variable differently

import Constants from 'expo-constants';

Read all about it here on the expo documentation site

answered Feb 25 '20 at 08:16

Adam Diament

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knot22 · Answer 7 · 2020-02-24T02:25:37.363

When trying to use this line

import { Constants } from 'expo-constants';

Constants was showing up as undefined when logged to the console.

However, this code worked to display the app's version:

<template>
  <text>version: {{ appVersion }}</text>
</template>

<script>

import * as Constants from 'expo-constants';

export default {
  data() {
    return {
      appVersion: Constants['default']['manifest']['version']
    }
  }
}
</script>

Read app.json (or exp.json) programmatically

7 Answers7