TypeError: Cannot read property '_location' of null

Basic info:

Node.js version: v8.9.1
jsdom version: 11.6.0

Minimal reproduction case

When there is a network request, if the window is closed after the message is sent but before the message is received, the code will continue to run and any window access will result in this kind of error:

(node:15703) TypeError: Cannot read property '_location' of null
    at Window.get location [as location] (/Users/Stefan/Desktop/Work/html-render/node_modules/jsdom/lib/jsdom/browser/Window.js:188:79)
    at fetch.then.then (./script.js:2:10)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)

In this example I polyfill fetch and make a request from an external script. As soon as the window loads I close it.

main.js

const jsdom = require("jsdom");
const { JSDOM } = jsdom;
const window = (new JSDOM(`<html>
    <head></head>
    <body>
        <script src="./script.js"></script>
    </body>
</html>`, {
  runScripts: "dangerously",
  resources: 'usable',
})).window;

window.fetch = require('node-fetch');

window.onload = () => {
  window.close();
};

script.js

fetch('https://api.ipify.org').then(x => x.text()).then((ip) => {
  window.location.href = ip;
});

How does similar code behave in browsers?

Window closes and any network request is aborted.

Since fetch in this case is an external implementation and uses node’s I/O callback, i’m not sure how that callback can be stopped.

Issue Analytics

State:
Created 6 years ago
Reactions:2
Comments:12 (6 by maintainers)

Top GitHub Comments

4reactions

merrywhethercommented, Sep 27, 2021

For me, this arose from updating jest-environment-jsdom from 27.0.6 to 27.2.2, which both rely on jsdom@^16.6.0.

The issue in this case was a call to self.close() after a promise resolved inside of some WebWorker code that was under test (and previously working). Replacing the spy on window.close with a full mock fixed the issue, seemingly pointing to the promise escaping the test lifetime. This thread pointed me towards window methods and async, but it seemed like Jest might be the root cause for my instance of this given the stable jsdom version.

3reactions

legraphistacommented, Jan 22, 2018

Yup, looks like anything that has to do with node’s I/O will trigger this, here’s another example:

main.js

const jsdom = require("jsdom");
const { JSDOM } = jsdom;
const { spawn } = require('child_process');

const window = (new JSDOM(`<html>
    <head></head>
    <body>
        <script src="./script.js"></script>
    </body>
</html>`, {
  runScripts: "dangerously",
  resources: 'usable',
})).window;

window.sleep = (cb) => {
  const p = spawn('sleep', [1]);
  p.on('close', cb);
};

window.onload = () => {
  setTimeout(() => window.close(), 100);
};

script.js

sleep(() => window.location.href);

Results in:

Stefans-MacBook:html-render Stefan$ node --trace-warnings main.js 
/Users/Stefan/Desktop/Work/html-render/node_modules/jsdom/lib/jsdom/browser/Window.js:188
      return idlUtils.wrapperForImpl(idlUtils.implForWrapper(window._document)._location);
                                                                              ^

TypeError: Cannot read property '_location' of null
    at Window.get location [as location] (/Users/Stefan/Desktop/Work/html-render/node_modules/jsdom/lib/jsdom/browser/Window.js:188:79)
    at ChildProcess.sleep (./script.js:1:20)
    at emitTwo (events.js:126:13)
    at ChildProcess.emit (events.js:214:7)
    at maybeClose (internal/child_process.js:925:16)
    at Socket.stream.socket.on (internal/child_process.js:346:11)
    at emitOne (events.js:116:13)
    at Socket.emit (events.js:211:7)
    at Pipe._handle.close [as _onclose] (net.js:554:12)

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