Cypress spec preprocessor that adds the "async / await" syntax
š Covered in my Cypress Plugins course
@cypress/browserify-preprocessor
to @cypress/webpack-batteries-included-preprocessor
for bundling transpiled specAdd this package as a dev dependency
$ npm i -D cypress-await
# or using Yarn
$ yarn add -D cypress-await
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)
})
})
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)
})
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'
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.
Start Cypress with OS environment variable DEBUG=cypress-await
# on Mac or Linux
$ DEBUG=cypress-await npx cypress open
To see even more output enable the verbose debug logs with DEBUG=cypress-await:verbose
# on Mac or Linux
$ DEBUG=cypress-await:verbose npx cypress open
Author: Gleb Bahmutov <gleb.bahmutov@gmail.com> © 2023
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
Copyright (c) 2023 Gleb Bahmutov <gleb.bahmutov@gmail.com>
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.