Local variables in Postman - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are local variables in Postman?

Local variables in Postman are variables that exist only during the execution of a single request or script. They are temporary and get deleted after the request finishes.

beginner

How do local variables differ from environment variables in Postman?

Local variables last only during one request execution, while environment variables persist across multiple requests and collections until changed or deleted.

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How do you set a local variable in a Postman test script?

Use `pm.variables.set('variableName', 'value')` inside the script to create or update a local variable.

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How do you get the value of a local variable in Postman?

Use `pm.variables.get('variableName')` to retrieve the value of a local variable during the request execution.

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Why use local variables instead of environment variables in Postman?

Local variables are useful for temporary data that only matters during one request, avoiding clutter or accidental reuse in other requests.

Which Postman method sets a local variable?

A pm.environment.set()

B pm.collectionVariables.set()

C pm.globals.set()

D pm.variables.set()

pm.variables.set() sets a local variable that lasts only during the current request execution.

How long do local variables last in Postman?

A Until manually deleted

B Only during the current request execution

C Until the environment is cleared

D Forever across all requests

Local variables exist only during the current request execution and are deleted afterward.

Which method retrieves a local variable's value in Postman?

A pm.globals.get()

B pm.environment.get()

C pm.variables.get()

D pm.collectionVariables.get()

pm.variables.get() retrieves the value of a local variable during the request execution.

Why might you prefer local variables over environment variables?

A They avoid clutter by being temporary

B They are easier to share

C They are stored permanently

D They persist across requests

Local variables are temporary and help avoid clutter by not persisting beyond the current request.

Which of these is NOT a scope for variables in Postman?

A Session variables

B Environment variables

C Local variables

D Global variables

Postman does not have 'session variables' as a scope; it uses local, environment, global, and collection variables.

Explain what local variables are in Postman and how to use them in a test script.

Think about variables that only live during one request.

Compare local variables and environment variables in Postman. When would you use each?

Consider how long you want the variable to last.

Practice

1. What is the main purpose of local variables in Postman?

easy

A. To create global environment settings

B. To save data permanently across all requests

C. To share data between different collections

D. To store data only during a single request execution

Solution

1. Step 1: Understand local variable scope

   Local variables exist only during the execution of one request and are not saved beyond that.

2. Step 2: Compare with other variable types

   Global or environment variables persist beyond one request, unlike local variables.

3. Final Answer:

   To store data only during a single request execution -> Option D

4. Quick Check:

   Local variables = single request scope [OK]

Hint: Local variables last only during one request [OK]

Common Mistakes:

• Confusing local variables with global variables
• Thinking local variables persist across requests
• Assuming local variables share data between collections

2. Which of the following is the correct syntax to set a local variable named token with value abc123 in Postman?

easy

A. pm.local.set('token', 'abc123');

B. pm.environment.set('token', 'abc123');

C. pm.variables.set('token', 'abc123');

D. pm.globals.set('token', 'abc123');

Solution

1. Step 1: Identify the correct method for local variables

   Local variables use pm.variables.set to assign values.

2. Step 2: Check other options for correctness

   pm.environment.set and pm.globals.set set environment and global variables, not local. pm.local.set is invalid.

3. Final Answer:

   pm.variables.set('token', 'abc123'); -> Option C

4. Quick Check:

   Set local variable = pm.variables.set [OK]

Hint: Use pm.variables.set() for local variables [OK]

Common Mistakes:

• Using pm.environment.set instead of pm.variables.set
• Trying to use pm.local.set which does not exist
• Confusing global and local variable methods

3. Consider this Postman test script:

pm.variables.set('count', 5);
pm.variables.set('count', pm.variables.get('count') + 3);
console.log(pm.variables.get('count'));

What will be printed in the console?

medium

A. 8

B. 5

C. Error: Cannot add number to undefined

D. null

Solution

1. Step 1: Set initial local variable 'count'

   The first line sets 'count' to 5.

2. Step 2: Increment 'count' by 3

   The second line gets 'count' (5), adds 3, and sets it back to 8.

3. Step 3: Output the updated value

   The console.log prints the current value of 'count', which is 8.

4. Final Answer:

   8 -> Option A

5. Quick Check:

   5 + 3 = 8 [OK]

Hint: Get then set to update local variable value [OK]

Common Mistakes:

• Assuming the variable does not update
• Expecting an error due to type mismatch
• Confusing local with environment variables

4. You wrote this Postman script:

pm.variables.set('user', 'Alice');
console.log(pm.variables.get('username'));

What is the problem here?

medium

A. Variable 'username' was never set, so get returns undefined

B. Syntax error in pm.variables.set method

C. Local variables cannot be logged to console

D. pm.variables.get requires two arguments

Solution

1. Step 1: Check variable names used

   The script sets 'user' but tries to get 'username', which was never set.

2. Step 2: Understand get behavior for unset variables

   Getting an unset local variable returns undefined, no error occurs.

3. Final Answer:

   Variable 'username' was never set, so get returns undefined -> Option A

4. Quick Check:

   Unset variable get = undefined [OK]

Hint: Check variable names carefully for typos [OK]

Common Mistakes:

• Assuming syntax error when variable name mismatches
• Thinking pm.variables.get needs two arguments
• Believing console.log cannot show local variables

5. You want to store a temporary token during a request and use it in multiple tests within that request. Which approach correctly uses local variables to achieve this?

hard

A. Set the token with pm.environment.set('token', 'abc') and get it with pm.variables.get('token')

B. Set the token once with pm.variables.set('token', 'abc') and get it in tests with pm.variables.get('token')

C. Set the token with pm.variables.set('token', 'abc') but cannot access it in other tests

D. Set the token with pm.globals.set('token', 'abc') and get it with pm.variables.get('token')

Solution

1. Step 1: Understand local variable scope within one request

   Local variables set with pm.variables.set are accessible throughout the request execution, including multiple tests.

2. Step 2: Verify correct get method usage

   Use pm.variables.get to retrieve the local variable value within the same request.

3. Step 3: Check other options for scope mismatch

   Environment and global variables persist beyond one request and are not local. Also, local variables are accessible across tests in the same request.

4. Final Answer:

   Set the token once with pm.variables.set('token', 'abc') and get it in tests with pm.variables.get('token') -> Option B

5. Quick Check:

   Local variable set/get works within one request [OK]

Hint: Use pm.variables.set/get to share data within one request [OK]

Common Mistakes:

• Using environment or global variables instead of local
• Thinking local variables cannot be shared between tests in one request
• Mixing set and get methods from different scopes