I have a method which uses DOMParser to parse a XML, like this:

this.parseXmlString = function(xmlDocStr) {
    var xmlDoc;
    var parser= new window.DOMParser();

    xmlDoc = parser.parseFromString( xmlDocStr, "text/xml" );
    // here I do some stuff with xmlDoc

    return xmlDoc;
};

The problem is: when I try to make a unit test with Jest of this function window.DOMParser is undefined. The test is as simple as:

expect(x2js.parseXmlString(xmlDocStr)).toMatchObject(expectedObject);

Is there any way I can use DOMParser from a Jest unit test?

I have a method which uses DOMParser to parse a XML, like this:

this.parseXmlString = function(xmlDocStr) {
    var xmlDoc;
    var parser= new window.DOMParser();

    xmlDoc = parser.parseFromString( xmlDocStr, "text/xml" );
    // here I do some stuff with xmlDoc

    return xmlDoc;
};

The problem is: when I try to make a unit test with Jest of this function window.DOMParser is undefined. The test is as simple as:

expect(x2js.parseXmlString(xmlDocStr)).toMatchObject(expectedObject);

Is there any way I can use DOMParser from a Jest unit test?

• javascript
• unit-testing
• jestjs
• domparser

2 Answers 2

You don't need to window reference. Just use new DOMParser().... Make sure you have "testEnvironment": "jsdom" in your Jest configuration (it should be the default though).

I've created an example here. https://repl.it/@ChrisPaton/FlusteredNearDecimal

You will also most likely need the latest version of Jest, as jsdom only added support for DOMParser and XMLSerializer in late October.

Update

JSDom is not supported above v11 by Jest. You'll need to configure a custom environment for this. Here is a link to their documentation and here is a link to a custom jsdom environment that is easy to use. I hope this helps.

On recent jest version (>28) you just have to install jest-environment-jsdom and change your test environment.

In package.json

"jest-environment-jsdom": "^29.7.0",

Then the environment either in the jest config file

testEnvironment: 'jsdom',

or by adding a @jest-environment docblock at the top of the file for all tests in that file:

/**
 * @jest-environment jsdom
 */

https://jestjs.io/docs/configuration#testenvironment-string