Write to a file with the specified contents.
Syntax
cy.writeFile(filePath, contents) cy.writeFile(filePath, contents, encoding) cy.writeFile(filePath, contents, options)
Usage
Correct Usage
cy.writeFile('menu.json')
Arguments
filePath (String)
A path to a file within the project root (the directory that contains the default cypress.json
).
contents (String, Array, or Object)
The contents to be written to the file.
encoding (String)
The encoding to be used when writing to the file. The following encodings are supported:
ascii
base64
binary
hex
latin1
utf8
utf-8
ucs2
ucs-2
utf16le
utf-16le
options (Object)
Pass in an options object to change the default behavior of cy.writeFile()
.
Option | Default | Description |
---|---|---|
log | true | Displays the command in the Command log |
flag | w | File system flag as used with fs.writeFile
|
encoding | utf8 | The encoding to be used when writing to the file |
To use encoding with other options, have your options object be your third parameter and include encoding there. This is the same behavior as
fs.writeFile
.
Yields
cy.writeFile()
yields the value of thecontents
argument.
Examples
Text
Write some text to a txt
file
If the path to the file does not exist, the file and its path will be created. If the file already exists, it will be over-written.
cy.writeFile('path/to/message.txt', 'Hello World') cy.readFile('path/to/message.txt').then((text) => { expect(text).to.equal('Hello World') // true })
{projectRoot}/path/to/message.txt
will be created with the following contents:
"Hello World"
JSON
Write JSON to a file
JavaScript arrays and objects are stringified and formatted into text.
cy.writeFile('path/to/data.json', { name: 'Eliza', email: '[email protected]' }) cy.readFile('path/to/data.json').then((user) => { expect(user.name).to.equal('Eliza') // true })
{projectRoot}/path/to/data.json
will be created with the following contents:
{ "name": "Eliza", "email": "[email protected]" }
Write response data to a fixture file
cy.request('https://jsonplaceholder.typicode.com/users').then((response) => { cy.writeFile('cypress/fixtures/users.json', response.body) }) // our fixture file is now generated and can be used cy.fixture('users').then((users) => { expect(users[0].name).to.exist })
Encoding
Specify the encoding as a String
cy.writeFile('path/to/ascii.txt', 'Hello World', 'ascii'))
{projectRoot}/path/to/message.txt
will be created with the following contents:
Hello World
Specify the encoding as part of the options object
cy.writeFile('path/to/ascii.txt', 'Hello World', { encoding: 'ascii', flag: 'a+' })
Flags
Append contents to the end of a file
cy.writeFile('path/to/message.txt', 'Hello World', { flag: 'a+' })
Rules
Requirements
cy.writeFile()
requires being chained off ofcy
.cy.writeFile()
requires the file be successfully written to disk. Anything preventing this such as OS permission issues will cause it to fail.
Assertions
cy.writeFile()
will only run assertions you've chained once, and will not retry.
Timeouts
cy.writeFile()
should never time out.
Because
cy.writeFile()
is asynchronous it is technically possible for there to be a timeout while talking to the internal Cypress automation APIs. But for practical purposes it should never happen.
Command Log
Write an array to a file
cy.writeFile('info.log', ['foo', 'bar', 'baz'])
The command above will display in the Command Log as:
When clicking on the writeFile
command within the command log, the console outputs the following:
History
Version | Changes |
---|---|
4.0.0 |
cy.writeFile() now yields null instead of contents
|
3.1.1 | Added flag option and appending with a+
|
1.0.0 |
cy.writeFile() command added |