Writing to files (cy.writeFile) in Cypress - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to write the string 'Hello World' to a file named 'greeting.txt'.

Cypress

cy.[1]('greeting.txt', 'Hello World')

Drag options to blanks, or click blank then click option'

Avisit

Bget

CwriteFile

DreadFile

Attempts:

3 left

💡 Hint

Common Mistakes

Using cy.readFile instead of cy.writeFile

Forgetting to specify the file name

Using cy.visit which is for visiting URLs

The cy.writeFile command writes data to a file. Here, it writes 'Hello World' to 'greeting.txt'.

2fill in blank

medium

Complete the code to write an object { name: 'Alice' } to 'user.json' as JSON.

Cypress

cy.[1]('user.json', { name: 'Alice' })

Drag options to blanks, or click blank then click option'

AwriteFile

Blog

Crequest

DreadFile

Attempts:

3 left

💡 Hint

Common Mistakes

Using cy.readFile instead of cy.writeFile

Trying to write objects with cy.log

Using cy.request which is for HTTP calls

cy.writeFile can write objects as JSON to files. Here, it writes the object to 'user.json'.

3fill in blank

hard

Fix the error in the code to correctly write 'Test data' to 'data.txt'.

Cypress

cy.writeFile('data.txt', [1])

Drag options to blanks, or click blank then click option'

AwriteFile

B'Test data'

CTest data

Dcy.writeFile

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the string data

Passing the command name instead of data

Using cy.writeFile inside the argument

The data to write must be a string or object. It must be quoted as a string literal. Without quotes, it causes an error.

4fill in blank

hard

Fill both blanks to write an array ['apple', 'banana'] to 'fruits.json' as JSON.

Cypress

cy.[1]('fruits.json', [2])

Drag options to blanks, or click blank then click option'

AwriteFile

BreadFile

C['apple', 'banana']

D{apple: 'banana'}

Attempts:

3 left

💡 Hint

Common Mistakes

Using cy.readFile instead of cy.writeFile

Passing an object instead of an array

Passing the array as a string

cy.writeFile writes data to files. The data here is an array, so it must be passed as is (not as a string).

5fill in blank

hard

Fill all three blanks to write a JSON object with uppercase keys to 'config.json'.

Cypress

const config = { [1]: 'value1', [2]: 'value2' };
cy.[3]('config.json', config);

Drag options to blanks, or click blank then click option'

A'API_KEY'

B'TIMEOUT'

CwriteFile

D'api_key'

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase keys instead of uppercase

Not quoting the keys

Using cy.readFile instead of cy.writeFile

The object keys are uppercase strings. The command to write the file is writeFile.

Practice

1. What is the main purpose of cy.writeFile() in Cypress testing?

easy

A. To delete a file after a test

B. To read data from a file during a test

C. To save data to a file during a test

D. To open a file in the browser

Solution

1. Step 1: Understand the function's role

   cy.writeFile() is used to save or write data into a file during Cypress tests.

2. Step 2: Differentiate from similar functions

   cy.readFile() reads data, but cy.writeFile() writes data. Deleting or opening files is not its purpose.

3. Final Answer:

   To save data to a file during a test -> Option C

4. Quick Check:

   Write data = A [OK]

Hint: Remember: writeFile writes, readFile reads [OK]

Common Mistakes:

• Confusing writeFile with readFile
• Thinking it deletes files
• Assuming it opens files in browser

2. Which of the following is the correct syntax to write the string 'Hello World' to a file named 'greeting.txt' using cy.writeFile()?

easy

A. cy.writeFile('greeting.txt', {text: 'Hello World'})

B. cy.writeFile('greeting.txt', 'Hello World')

C. cy.writeFile('greeting.txt' => 'Hello World')

D. cy.writeFile('greeting.txt', ['Hello World'])

Solution

1. Step 1: Identify correct parameter usage

   cy.writeFile() takes the file path as first argument and the content as second argument, which can be a string.

2. Step 2: Check syntax correctness

   cy.writeFile('greeting.txt', 'Hello World') uses correct syntax: file path string and content string separated by a comma.

3. Final Answer:

   cy.writeFile('greeting.txt', 'Hello World') -> Option B

4. Quick Check:

   Correct syntax uses comma between path and content [OK]

Hint: Use comma between file path and content [OK]

Common Mistakes:

• Using arrow (=>) instead of comma
• Passing content inside an object unnecessarily
• Passing content as an array instead of string

3. Consider the following Cypress code snippet:

cy.writeFile('data.json', { name: 'Alice', age: 30 })
cy.readFile('data.json').then((content) => {
  console.log(content.age)
})

What will be printed in the console?

medium

A. undefined

B. Alice

C. { name: 'Alice', age: 30 }

D. 30

Solution

1. Step 1: Understand what is written to the file

   The object { name: 'Alice', age: 30 } is saved to 'data.json'.

2. Step 2: Understand what is logged

   The code reads the file and logs content.age, which is 30.

3. Final Answer:

   30 -> Option D

4. Quick Check:

   Accessing content.age logs 30 [OK]

Hint: Read file content and access property to get value [OK]

Common Mistakes:

• Expecting the whole object to print
• Confusing name and age values
• Assuming undefined because of async

4. You wrote this code to save JSON data:

cy.writeFile('user.json', '{"name": "Bob", "age": 25}')

But when you read the file, you get a string instead of an object. What is the problem?

medium

A. The JSON data is passed as a string, not as an object

B. The file path is incorrect

C. cy.writeFile cannot write JSON data

D. The file extension must be .txt

Solution

1. Step 1: Analyze the data argument

   The data is passed as a JSON string, not as a JavaScript object.

2. Step 2: Understand how cy.writeFile handles data

   If you pass a string, it writes it as a string. To write JSON, pass an object directly.

3. Final Answer:

   The JSON data is passed as a string, not as an object -> Option A

4. Quick Check:

   Pass object, not string, to write JSON [OK]

Hint: Pass object, not JSON string, to write JSON files [OK]

Common Mistakes:

• Passing JSON as string instead of object
• Blaming file path without checking data
• Thinking file extension affects JSON writing

5. You want to append a new line 'Test passed' to an existing file 'results.txt' using cy.writeFile(). Which code snippet correctly appends the text without overwriting the file?

hard

A. cy.writeFile('results.txt', 'Test passed', { flag: 'a+' })

B. cy.writeFile('results.txt', 'Test passed')

C. cy.writeFile('results.txt', 'Test passed', { overwrite: false })

D. cy.writeFile('results.txt', 'Test passed', { append: true })

Solution

1. Step 1: Understand file writing flags

   To append text, the file must be opened with append flag, which is 'a+' in Node.js.

2. Step 2: Check Cypress options for cy.writeFile

   Cypress supports passing { flag: 'a+' } to append instead of overwrite.

3. Final Answer:

   cy.writeFile('results.txt', 'Test passed', { flag: 'a+' }) -> Option A

4. Quick Check:

   Use flag 'a+' to append text [OK]

Hint: Use { flag: 'a+' } option to append text [OK]

Common Mistakes:

• Omitting flag option causes overwrite
• Using non-existent options like append: true
• Assuming overwrite: false appends text