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Create Counter Function

Certification: Basic Level Accuracy: 0% Submissions: 0 Points: 8

Write a JavaScript program to create a counter function using closures. The function should return another function that increments and returns a counter value each time it's called. Each counter instance should maintain its own independent count.

Example 1
    
  
  • Input: counter = createCounter(5)
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  • Output: counter() returns 6, counter() returns 7, counter() returns 8
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  • Explanation: 
    • Counter is initialized with starting value 5. 
    • First call increments to 6 and returns 6. 
    • Second call increments to 7 and returns 7. 
    • Third call increments to 8 and returns 8.
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Example 2
    
  
  • Input: counter1 = createCounter(0), counter2 = createCounter(10)
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  • Output: counter1() returns 1, counter2() returns 11, counter1() returns 2
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  • Explanation: 
    • Two independent counters are created with different starting values. 
    • counter1 starts at 0, counter2 starts at 10. 
    • Each counter maintains its own state independently. 
    • Calling counter1() returns 1, counter2() returns 11, counter1() returns 2.
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Constraints
    
  
  • -1000 ≤ initialValue ≤ 1000
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  • The counter function should use closures to maintain state
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  • Each counter instance should be independent
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  • Time Complexity: O(1) per function call
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  • Space Complexity: O(1) per counter instance
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Functions / MethodsTech MahindraShopify
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Hint
Solution

Solution Hints

    
  
  • Use a closure to encapsulate the counter variable within the outer function scope
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  • Return an inner function that has access to the counter variable
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  • The inner function should increment the counter and return the new value
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  • The counter variable will be preserved between function calls due to closure
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  • Each call to createCounter should create a new independent closure
    •

Steps to solve by this approach:

 Step 1: Create the outer function createCounter that accepts an initial value parameter.
 Step 2: Declare a local variable counter inside the outer function and initialize it with the initial value.
 Step 3: Return an inner anonymous function from the outer function.
 Step 4: Inside the inner function, increment the counter variable by 1.
 Step 5: Return the updated counter value from the inner function.
 Step 6: The closure mechanism ensures the counter variable persists between function calls.
 Step 7: Each call to createCounter creates a new independent closure with its own counter variable.

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