React Native Error - Can't find variable: self

Question

After adding a node module,isomorphic-fetch(version : ^2.2.1) in React Native app, I am getting an error of Can't find variable: self.
Here I have attached a screenshot.

The error is thrown from the file, located at node_modules > isomorphic-fetch > fetch-npm-browserify.js.
Following is the code of that file.

// the whatwg-fetch polyfill installs the fetch() function
// on the global object (window or self)
//
// Return that as the export for use in Webpack, Browserify etc.
require('whatwg-fetch');
module.exports = self.fetch.bind(self);

score 6 · Answer 1 · edited Feb 02 '17 at 18:58

6

@Nirav Dangi,按新建fetch-npm-react-native.js 的方式在我的项目里面没有起作用；我这边处理方式，是直接修改，node_modules > isomorphic-fetch > fetch-npm-browserify.js 文件的返回：

Google Translate: @Nirav Dangi, in accordance with the new way fetch-npm-react-native.js in my project which is not working; I am here to deal with direct changes, node_modules> isomorphic-fetch> fetch-npm-browserify.js file Back:

var globalObject = typeof self === "undefined" ? global : self;
module.exports = globalObject.fetch.bind(globalObject);
//module.exports = fetch;

edited Feb 02 '17 at 18:58

Anil

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answered Jun 20 '16 at 08:24

galaxybing

61
1

I am not good enough with the Chinese language. So far I understood by your code, it should work. Also, If you can see in my answer, I have just updated it and added #4 `npm install`. – Nirav Dangi Jun 20 '16 at 15:10

Nirav Dangi · Answer 2 · 2016-06-20T15:08:04.923

I have fixed this issue with the help of this answer,
https://github.com/matthew-andrews/isomorphic-fetch/pull/80

Specify a separate entry point for React Native that export React Native's fetch() polyfill.

Create an empty file named fetch-npm-react-native.js. Drop this file at node_modules > isomorphic-fetch location.
Add this line of code module.exports = fetch; to fetch-npm-react-native.js file.
Goto the file node_modules > isomorphic-fetch > package.json. In the package.json file, add "main": "fetch-npm-node.js", line of code.
Open Terminal, GoTo app directory and write npm install
Reload the app and here you go...

Ofcourse the credit goes to Jou

Thanks for pointing out that the problem is with 'isomorphic-fetch' package — jeevium, May 09 '18 at 13:09

Yossi · Answer 3 · 2018-12-17T12:14:21.443

0

I had the same problem, and the other solutions didn't work for me.

What I did was to replace

import 'isomorphic-fetch'

with this:

import 'cross-fetch'

This is based on the following: https://github.com/matthew-andrews/isomorphic-fetch/issues/125

edited Dec 17 '18 at 12:14

answered Dec 17 '18 at 11:45

Yossi

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React Native Error - Can't find variable: self

3 Answers3