What is the time and space complexity of Implement call()?

Time complexity: O(1). Space complexity: O(1).

Implement call()

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Solution Guide: Implement call()

Approach

Attach the target function as a temporary method on the context object using a Symbol key to avoid property collisions. Invoke it via context[fnKey](...args) so that this resolves to context, then clean up by deleting the temporary property.

Complexity Analysis

Time: O(1)
Space: O(1)

Pattern

Context Binding Polyfill

Why It Works

When a function is called as a method of an object (obj.fn()), JavaScript sets this to the object. By temporarily attaching the function to the desired context, we leverage implicit this binding.

Updated Mar 2026