A little Cypress.io plugin for waiting for network to be idle before continuing with the test
npm install cypress-network-idle> A little Cypress.io plugin for waiting for network to be idle before continuing with the test
- Cypress-network-idle plugin
- Prepare Intercept And Wait Using cypress-network-idle Plugin
Covered in my course 🎓 Cypress Network Testing
``install using NPM
npm i -D cypress-network-idleinstall using Yarn
yarn add -D cypress-network-idle
Import or require this plugin from the support file or from the spec file
`js`
import 'cypress-network-idle'
Wait for two seconds to pass without any network calls (Ajax, static resources)
`js`
cy.waitForNetworkIdle(2000)
Wait one second without any GET calls to /v1/api endpoint
`js`
cy.waitForNetworkIdle('/v1/api', 1000)
Wait for 5 seconds without any POST calls to /graphql endpoint
`js`
cy.waitForNetworkIdle('POST', '/graphql', 5000)
Wait for 5 seconds for any call (GET, POST, PUT, etc) to any endpoint
`js`
cy.waitForNetworkIdle('', '', 5000)
Wait for 5 seconds for any POST or GET to any endpoint
`js`
cy.waitForNetworkIdle('+(POST|GET)', '*', 5000)
For pattern matching see more examples in the cy.intercept() documentation.
Let's take this example
`js`
cy.waitForNetworkIdle('POST', '/graphql', 5000)
The 5000 argument is the wait number in milliseconds. The command will check for 5 seconds with _no_ POST /graphql calls. But how long do we need to wait for those idle 5 seconds? By default, it is the maximum of Cypress.config('responseTimeout') value (usually 30 seconds in Cypress) and the three times the wait amount (in our case 15 seconds).
You can set a longer time limit for waiting for network to be idle for 5 seconds. Let's wait for up to a minute for 5 second idle period:
`js`
cy.waitForNetworkIdle('POST', '/graphql', 5000, { timeout: 60_000 })
You can disable the log messages by adding option object with { log: false } property
`js`
cy.waitForNetworkIdle('/v1/api', 1000, { log: false })
Sometimes the network calls start early. For example, if the network calls are kicked off by the cy.visit you want to start capturing the timestamps before it, but wait for the network to be idle after. You can start listening using the prepare call like this.
`js`
cy.waitForNetworkIdlePrepare({
method: 'GET',
pattern: '*',
alias: 'calls',
})
cy.visit('/')
// now wait for the "@calls" to finish
cy.waitForNetworkIdle('@calls', 1000)
Notice the use of the alias parameter to correctly listen to the intercepted calls. You can disable logging by adding log: false to the prepare call
`js`
cy.waitForNetworkIdlePrepare({
method: 'GET',
pattern: '*',
alias: 'calls',
log: false,
})
You can wait multiple times for the prepared network alias.
`js`
cy.waitForNetworkIdlePrepare({
method: 'POST',
pattern: '/api/graphql',
alias: 'graphql',
})
cy.visit('/')
cy.waitForNetworkIdle('@graphql', 1000)
// the page has fully loaded
// interact with the page
cy.waitForNetworkIdle('@graphql', 1000)
// the page has finished additional processing
By default, the network calls might fail and the test happily continues. You can make the idle spy fail if any of the matching network calls return 4xx or 5xx errors. These classes of error status code have their own flag to enable.
`js`
// fail the test if any of the matching calls
// returns a 4xx status code
cy.waitForNetworkIdlePrepare({
method: '*',
alias: 'all',
pattern: '**',
failOn4xx: true,
})
!The test fails when one of the calls receives 401 from the server
`js`
// fail the test if any of the matching calls
// returns a 5xx status code
cy.waitForNetworkIdlePrepare({
method: '*',
alias: 'all',
pattern: '**',
failOn5xx: true,
})
!The test fails when one of the calls receives 500 from the server
You can write your own callback function failOn(req, res) to decide if the network call should fail the test. Can be useful to include additional information in the error message. For example, let's include the custom message headers:
`jsCall ${req.method} ${req.url} (x flag ${req.headers['x-my-flag']}) failed
cy.waitForNetworkIdlePrepare({
method: 'POST',
alias: 'post',
pattern: '/status-401',
failOn(req, res) {
if (res.statusCode === 401) {
return
}
},
})
All you need to do to fail the test is return an error message from the synchronous callback.
If you try to register the same intercept method, pattern, and alias multiple times, only a single first registration will be made.
`js`
cy.waitForNetworkIdlePrepare({
method: 'GET',
pattern: '/user',
alias: 'user',
})
// this registration will be ignored
cy.waitForNetworkIdlePrepare({
method: 'GET',
pattern: '/user',
alias: 'user',
})
// this registration will be ignored
cy.waitForNetworkIdlePrepare({
method: 'GET',
pattern: '/user',
alias: 'user',
})
If there are ongoing network calls, this plugin waits for them to resolve before checking for network idle, see the after.js spec.
The command yields an object with a few timestamps and the number of network calls. See the src/index.d.ts for precise fields
`js`
cy.waitForNetworkIdle(2000)
// check how long the command waited
.its('waited')
// it should have waited for at least 2 seconds
// but could be up to 3 seconds if the app
// made a call one second after the start
.should('be.within', 2000, 3000)
You can limit which requests to consider by using method and pattern parameters. For example, see the spec get-vs-post.js
`js
// listen to all POST calls
cy.waitForNetworkIdlePrepare({
method: 'POST',
pattern: '*',
alias: 'postCalls',
})
cy.visit('/get-vs-post')
cy.waitForNetworkIdle('@postCalls', 2000)
`
`js
// listen to "POST /add-user" calls
cy.waitForNetworkIdlePrepare({
method: 'POST',
pattern: '/add-user',
alias: 'addUser',
})
cy.visit('/get-vs-post')
cy.waitForNetworkIdle('@addUser', 2000)
`
If you always want to want for network idle when calling cy.visit you can overwrite this command using the provided code in src/register.js file
`js
// your spec
const { registerVisit } = require('cypress-network-idle/src/register')
registerVisit({ timeout: 1000 })
it('waits for network idle', () => {
cy.visit('/')
// the network has been idle for 1 second
})
`
If waiting for all network calls to finish and for network to be idle for N milliseconds fails, the plugin prints all outstanding (current) network calls
This plugin includes the TypeScript types, import them from your JavaScript files using the reference types comment or via TS config.
`js``
///
This plugin uses the timestamp of the request and the response to compute the idle timestamp. This helps with any longer-running requests - the idle time is computed from their completion.
Author: Gleb Bahmutov <gleb.bahmutov@gmail.com> © 2021
- @bahmutov
- glebbahmutov.com
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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) 2021 Gleb Bahmutov <gleb.bahmutov@gmail.com>
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