cypress-wait-until

Add the Cypress waiting power to virtually everything 🎉

Use this plugin to wait for everything not expected by Cypress wait.

Installation

npm i -D cypress-wait-until
# or
yarn add -D cypress-wait-until

Usage

cypress-wait-until extends Cypress' cy command.

Add this line to your project's cypress/support/commands.js:

import 'cypress-wait-until';

Then, in your test, you can write

// wait until a cookie is set
cy.waitUntil(() => cy.getCookie('token').then(cookie => Boolean(cookie && cookie.value)));

// wait until a global variable has an expected value
cy.waitUntil(() => cy.window().then(win => win.foo === "bar"));

// sync function works too!
cy.waitUntil(() => true);

// with all the available options
cy.waitUntil(() => cy.window().then(win => win.foo === "bar"), {
  errorMsg: 'This is a custom error message', // overrides the default error message
  timeout: 2000, // waits up to 2000 ms, default to 5000
  interval: 500 // performs the check every 500 ms, default to 200
});

If you return a truthy value, it becomes the subject for the next command. So you can assert about it too

// wait until the Recaptcha token will be added to the dedicated hidden input field...
cy.waitUntil(() => cy.get("input[type=hidden]#recaptchatoken").then($el => $el.val()))
  // ... then, check that it's valid string asserting about it
  .then(token => expect(token).to.be.a("string").to.have.length.within(1, 1000));

The waitUntil command could be chained to other commands too. As an example, the following codes are equivalent

cy.waitUntil(() => cy.getCookie('token').then(cookie => cookie.value === '<EXPECTED_VALUE>'));
// is equivalent to
cy.wrap('<EXPECTED_VALUE>')
  .waitUntil((subject) => cy.getCookie('token').then(cookie => cookie.value === subject));

Please note

do not expect that the previous command is retried. Only what's inside the checkFunction body is retried

cy.getCookie('token') // will not be retried
  .waitUntil(cookie => cookie.value === '<EXPECTED_VALUE>');

you cannot put assertions inside checkFunction. There is no way to avoid a test failure if an assertion throws an error. You must manually check what the assertions would check for you. The most common case is checking that an element exists or not, instead of using cy.get('#id').should('exist') you should check that Cypress.$('#id').length is greater than 0. Here you can find a deeper explanation

TypeScript

If you use TypeScript you can define the checkFunction returning type too. Take a look at the plugin.spec.ts file to read about the cy.waitUntil signature.

IMPORTANT:

Remember to add cypress-wait-until to the cypress/tsconfig.json file

{
  "compilerOptions": {
    "types": ["cypress", "cypress-wait-until"]
    }
  }
}

If you are encountering "cy.waitUntil is not a function" or "cy.waitUntil is undefined", you might need to specify the support file in your cypress.json for the import to work correctly:

{
  "supportFile": "cypress/support/commands.ts"
}

Arguments

checkFunction

A function that must return a truthy value when the wait is over.

options:Object (optional)

Pass in an options object to change the default behavior of cy.waitUntil().

Option	Type	Default	Description
`errorMsg`	`string` \| `function`	`"Timed out retrying"`	The error message to write. If it's a function, it will receive the last result and the options passed to `cy.waitUntil`
`timeout`	`number`	`5000`	Time to wait for the `checkFunction` to return a truthy value before throwing an error.
`interval`	`number`	`200`	Time to wait between the `checkFunction` invocations.
`description`	`string`	`"waitUntil"`	The name logged into the Cypress Test Runner.
`logger`	`function`	`Cypress.log`	A custom logger in place of the default Cypress.log. It's useful just for debugging purposes.
`log`	`boolean`	`true`	Enable/disable logging.
`customMessage`	`string`	`undefined`	String logged after the `options.description`.
`verbose`	`boolean`	`false`	If every single check result must be logged.
`customCheckMessage`	`string`	`undefined`	Like `customMessage`, but used for every single check. Useless if `verbose` is not set to `true`.

Log options are a lot, take a look at the next screenshot to understand how they are printed

Could cy.waitUntil avoid failing the test?

No. cy.waitUntil waits for something that must happen, otherwise the test will fail. Cypress enforces to avoid conditional testing and the plugin agrees with that.

There are cases where conditional testing makes sense but if cy.waitUntil would have this capability everyone will use it to create conditional tests, treating the Cypress feature—because avoiding conditional testing is a feature—as "a bug".

If you need conditional testing you could write your own recursive promise check function (take a look here and here where it is explained how to do that) where you manage your case. After all, cy.waitUntil is just a recursive promise manager 😊

Why did we write it?

A lot of StackOverflow users had some difficulties in implementing a recursive promise with Cypress just to repeatedly check for something to happen (see two of the various questions about the topic: How can i wait for each element in a list to update to a certain text? And How do I wait until a cookie is set?).
This plugin is dedicated to them ❤️

Open Source Saturday

This project has been made during one of the Open Source Saturdays, a series of Milan-based events where everyone codes just to spread some Open Source love ❤️

Contributing

Contributes are welcome, if you need to run the tests through npm test, you must update the package.json configuration setting cypressUploadRecordings to false (or set your own Cypress recording key).

Contributors

Thanks goes to these wonderful people (emoji key):

_{Stefano Magni} 💻 ⚠️ 📖	_{Tommaso Allevi} 💻 ⚠️	_brogueady 💻	_seeu1 🤔	_{Sarah Weir} 🐛 💻	_{Lee Alexis} 📖	_{Phil Burrows} 🤔 💻 ⚠️
_{Leo Viezens} 📖