cypress-await

Cypress spec preprocessor that adds the "async / await" syntax

Examples

📝 Read blog post Use Async Await In Cypress Specs
📺 Watch video Await Cypress Command Results
📺 Watch video cypress-await Sync Mode Example
🖥️ Repo bahmutov/cypress-todomvc-await-example

Todos

switch from @cypress/browserify-preprocessor to @cypress/webpack-batteries-included-preprocessor for bundling transpiled spec
support relative require and import statements in the transpiled specs #9
support absolute require and import statements in the transpiled specs #10

Install

Add this package as a dev dependency

$ npm i -D cypress-await
# or using Yarn
$ yarn add -D cypress-await

Use as a preprocessor

Add the following to your cypress.config.js file:

// cypress.config.js
const { defineConfig } = require('cypress')
// https://github.com/bahmutov/cypress-await
const cyAwaitPreprocessor = require('cypress-await/src/preprocessor')

module.exports = defineConfig({
  e2e: {
    setupNodeEvents(on, config) {
      on('file:preprocessor', cyAwaitPreprocessor())
    },
  },
})

In your spec files you can use value = await cy... instead of cy....then(value => )

it('shows the number of projects', async () => {
  await cy.visit('/')
  const n = await cy.get('#projects-count').invoke('text').then(parseInt)
  cy.log(n)
  expect(n, 'number of projects').to.be.within(350, 400)
})

The above code is equivalent to the "plain" Cypress test

it('shows the number of projects', () => {
  cy.visit('/')
  cy.get('#projects-count')
    .invoke('text')
    .then(parseInt)
    .then((n) => {
      cy.log(n)
      expect(n, 'number of projects').to.be.within(350, 400)
    })
})

Preprocessor sync mode

It might seem redundant to always write n = await cy..., thus there is a "sync" mode preprocessor where you can write the spec code without using await before each Cypress chain.

// cypress.config.js
const { defineConfig } = require('cypress')
// https://github.com/bahmutov/cypress-await
const cyAwaitPreprocessor = require('cypress-await/src/preprocessor-sync-mode')

module.exports = defineConfig({
  e2e: {
    setupNodeEvents(on, config) {
      on('file:preprocessor', cyAwaitPreprocessor())
    },
  },
})

We can get the parsed number of projects from the page

it('shows the number of projects', () => {
  cy.visit('/')
  const n = cy.get('#projects-count').invoke('text').then(parseInt)
  cy.log(n)
  expect(n, 'number of projects').to.be.within(350, 400)
})

Transform some spec files

You can apply this preprocessor only to some specs using minimatch over the full spec source filepath

setupNodeEvents(on, config) {
  on('file:preprocessor', cyAwaitPreprocessor({
    specPattern: '**/*.sync.cy.js'
  }))
}

For simplicity, you can also use the end of the files that need to be transpiled. For example, to transpile all files that end with .sync.cy.js, you can use specPattern: '.sync.cy.js'

Show transpiled output

Set the preprocessor with the debugOutput: true option

setupNodeEvents(on, config) {
  on('file:preprocessor', cyAwaitPreprocessor({
    debugOutput: true
  }))
}

The transpiled output will appear in the terminal.

Debugging

Start Cypress with OS environment variable DEBUG=cypress-await

# on Mac or Linux
$ DEBUG=cypress-await npx cypress open

Small print

License: MIT - do anything with the code, but don't blame me if it does not work.

Support: if you find any problems with this module, email / tweet / open issue on Github

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

X3mistSherX/cypress-await