waitForElement gets into infinite setTimeout loop

[grigasp]

• dom-testing-library version: 3.5.1
• node version: 8.11.2
• npm (or yarn) version: 5.6.0

Relevant code or config:

const { waitForElement } = require("dom-testing-library");

it("shouldn't hang after succeeding", async () => {
    let didMakeMutation = false;
    const createElement = () => document.createElement("div");
    const container = createElement();
    const myCallback = () => {
        return didMakeMutation;
    };
    const result = waitForElement(myCallback, { container });
    container.appendChild(createElement());
    didMakeMutation = true;
    await new Promise((resolve) => setTimeout(resolve, 50));
});

What you did:

I'm trying to use waitForElement to wait until an element is created in the dom.

What happened:

I found that my test is passing, but the test runner (mocha) doesn't exit - it gets into infinite setTimeout loop.

Reproduction:

Repo: https://github.com/grigasp/dom-testing-library-waitforelement-issue

npm install
npm run test

Problem description:

The test succeeds, but the test runner (mocha) doesn't ever exit, because waitForElement gets into infinite setTimeout loop.

I think the problem is that waitForElement calls observer.disconnect() from the onMutation() -> onDone() callback. MutationObserver, after calling the onMutation() callback, immediately recreates the listener, and then gets into the infinite setTimeout loop.

Suggested solution:

waitForElement should somehow call disconnect() after MutationObserver recreates the listener.

[kentcdodds]

I'm not certain I follow you, but if I could see the code changes you're asking for I probably would. Could you make a pull request?

[kentcdodds]

🎉 This issue has been resolved in version 3.5.2 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀