cy.first(), cy.last(), cy.eq() in Cypress - Build an Automation Script

Verify cy.first(), cy.last(), and cy.eq() commands on a list of items

Preconditions (2)

Step 1: Open the web page with the list of items.

Step 2: Use cy.get() to select all elements with class 'item' inside the 'item-list'.

Step 3: Use cy.first() to get the first item and verify its text is 'Item 1'.

Step 4: Use cy.last() to get the last item and verify its text is 'Item 5'.

Step 5: Use cy.eq(2) to get the third item (index 2) and verify its text is 'Item 3'.

✅ Expected Result: The first item text is 'Item 1', the last item text is 'Item 5', and the third item text is 'Item 3'. All assertions pass.

Automation Requirements - Cypress

Assertions Needed:

Verify the text of the first item is 'Item 1'.

Verify the text of the last item is 'Item 5'.

Verify the text of the third item (index 2) is 'Item 3'.

Best Practices:

Use cy.get() with a clear and specific CSS selector.

Use cy.first(), cy.last(), and cy.eq() to select elements by position.

Use should('have.text', expectedText) for assertions.

Avoid hardcoding selectors that are brittle.

Use descriptive test names.

Automated Solution

Cypress

describe('Test cy.first(), cy.last(), and cy.eq() commands', () => {
  beforeEach(() => {
    cy.visit('/items-page')
  })

  it('should verify first, last, and eq selectors on item list', () => {
    cy.get('.item-list .item').first().should('have.text', 'Item 1')
    cy.get('.item-list .item').last().should('have.text', 'Item 5')
    cy.get('.item-list .item').eq(2).should('have.text', 'Item 3')
  })
})

This test suite visits the page with the list of items before each test.

The test uses cy.get() to select all items with the class item inside the container item-list.

Then it uses cy.first() to get the first item and asserts its text is 'Item 1'. Similarly, cy.last() gets the last item and asserts its text is 'Item 5'. Finally, cy.eq(2) selects the third item (index 2) and asserts its text is 'Item 3'.

Assertions use should('have.text', ...) to check the exact text content.

This approach is clear, uses best practices, and the selectors are specific and maintainable.

Common Mistakes - 4 Pitfalls

Using cy.get() multiple times for the same selector instead of chaining

Using hardcoded XPath selectors instead of CSS selectors

Using .eq() with an out-of-range index

{'mistake': "Using .should('contain', text) instead of .should('have.text', text) for exact match", 'why_bad': 'Contain checks partial text and may pass incorrectly.', 'correct_approach': "Use .should('have.text', text) to assert exact text content."}

Bonus Challenge

Now add data-driven testing to verify first, last, and eq(2) items for 3 different lists with different item texts.

Show Hint

Practice

1. What does cy.first() do in Cypress testing?

easy

A. Selects all elements matching a selector

B. Selects the last element from a group of matched elements

C. Selects the first element from a group of matched elements

D. Selects an element by its CSS class

Solution

1. Step 1: Understand the purpose of cy.first()

   cy.first() is used to pick the very first element from a list of elements found by a selector.

2. Step 2: Compare with other options

   Options A, B, and C describe different behaviors: last element, selecting by class, or selecting all elements, which are not what cy.first() does.

3. Final Answer:

   Selects the first element from a group of matched elements -> Option C

4. Quick Check:

   cy.first() = first element [OK]

Hint: Remember: first() picks the very first element [OK]

Common Mistakes:

• Confusing first() with last()
• Thinking first() selects by class or id
• Assuming first() selects all elements

2. Which of the following is the correct syntax to select the third element in a list using Cypress?

easy

A. cy.get('li').eq(2)

B. cy.get('li').eq(3)

C. cy.get('li').first(3)

D. cy.get('li').last(3)

Solution

1. Step 1: Recall zero-based indexing in eq()

   The eq() command uses zero-based index, so the third element is at index 2.

2. Step 2: Check syntax correctness

   cy.get('li').eq(2) uses eq(2) correctly. Options A, C, and D either use wrong index or invalid syntax.

3. Final Answer:

   cy.get('li').eq(2) -> Option A

4. Quick Check:

   Third element index = 2 [OK]

Hint: Remember eq() uses zero-based index, so third is eq(2) [OK]

Common Mistakes:

• Using eq(3) for the third element
• Trying to pass a number to first() or last()
• Confusing eq() with first() or last()

3. Given the following HTML:

<ul>
  <li>Apple</li>
  <li>Banana</li>
  <li>Cherry</li>
  <li>Date</li>
</ul>

What text will cy.get('li').last().invoke('text') return?

medium

A. "Cherry"

B. "Apple"

C. "Banana"

D. "Date"

Solution

1. Step 1: Identify what cy.last() selects

   cy.last() picks the last element in the matched list, which is the <li> containing "Date".

2. Step 2: Understand invoke('text')

   This command extracts the text content of the selected element, so it returns "Date".

3. Final Answer:

   "Date" -> Option D

4. Quick Check:

   last() element text = "Date" [OK]

Hint: last() picks last element's text content [OK]

Common Mistakes:

• Selecting first element text instead of last
• Confusing zero-based index with last()
• Expecting eq(3) to return "Date" without zero-based indexing

4. Consider this Cypress code snippet:

cy.get('button').eq(5).click()

It throws an error: "Cannot read property 'click' of undefined". What is the most likely cause?

medium

A. There are fewer than 6 buttons on the page, so eq(5) returns undefined

B. The syntax of eq() is incorrect; it should be eq[5]

C. click() cannot be chained after eq()

D. The selector 'button' is invalid

Solution

1. Step 1: Understand eq() index and element count

   eq(5) tries to select the 6th element (index 5). If fewer than 6 buttons exist, it returns undefined.

2. Step 2: Analyze error message

   The error "Cannot read property 'click' of undefined" means the element does not exist, so click() fails.

3. Final Answer:

   There are fewer than 6 buttons on the page, so eq(5) returns undefined -> Option A

4. Quick Check:

   Index out of range = undefined element [OK]

Hint: Check element count before using eq(index) [OK]

Common Mistakes:

• Using wrong eq() syntax
• Assuming click() can't chain after eq()
• Ignoring zero-based index causing out-of-range

5. You want to click the second-to-last item in a list of elements matched by cy.get('.item'). Which Cypress command chain correctly achieves this?

hard

A. cy.get('.item').eq(cy.get('.item').its('length').then(len => len - 2)).click()

B. cy.get('.item').eq(-2).click()

C. cy.get('.item').eq(-1).click({ force: true })

D. cy.get('.item').eq(cy.get('.item').length - 2).click()

Solution

1. Step 1: Recall eq() indexing in Cypress

   Cypress eq(n) supports negative indices: eq(-1) is last, eq(-2) is second-to-last.

2. Step 2: Compare options

   Options A and B have invalid syntax passing chainables to eq(). cy.get('.item').eq(-1).click({ force: true }) uses eq(-1) for last item. cy.get('.item').eq(-2).click() correctly uses eq(-2).

3. Final Answer:

   cy.get('.item').eq(-2).click() -> Option B

4. Quick Check:

   eq(-2) = second-to-last [OK]

Hint: eq() supports negative indices: -2 for second-to-last [OK]

Common Mistakes:

• Using negative index in eq() incorrectly (e.g., -1 instead of -2)
• Trying to subtract length directly without .then()
• Passing Cypress chainable as eq() argument