Export syntax variations in Typescript - Time & Space Complexity

Time Complexity: Export syntax variations

O(n)

Understanding Time Complexity

When we use different export styles in TypeScript, the way the code runs can change how many steps it takes.

We want to see how the number of operations grows when exporting in different ways.

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

// Exporting multiple functions
export function add(a: number, b: number) { return a + b; }
export function multiply(a: number, b: number) { return a * b; }

// Exporting an object
export const mathOps = {
  add: (a: number, b: number) => a + b,
  multiply: (a: number, b: number) => a * b
};
    

This code shows two ways to export: separate named exports and a single object export.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: Exporting functions or objects is a one-time setup without loops.
• How many times: Each export runs once when the module loads.

How Execution Grows With Input

Exporting does not depend on input size; it happens once regardless of how many functions are exported.

Input Size (n)	Approx. Operations
1 function	1 operation
10 functions	10 operations
100 functions	100 operations

Pattern observation: Operations grow linearly with the number of exports, but each export is a simple assignment.

Final Time Complexity

Time Complexity: O(n)

This means the time to export grows directly with how many items you export, but each is simple and fast.

Common Mistake

[X] Wrong: "Exporting multiple functions is slow because it runs code many times."

[OK] Correct: Exporting just sets up references once; it does not repeatedly run the functions or loop over data.

Interview Connect

Understanding how export statements work helps you explain module design clearly and shows you know how code setup affects performance.

Self-Check

"What if we dynamically generate and export functions inside a loop? How would the time complexity change?"

Practice

1. Which of the following is the correct way to export a function named calculate as a named export in TypeScript?

easy

A. module.exports = calculate;

B. export default function calculate() { /*...*/ }

C. export = calculate;

D. export function calculate() { /*...*/ }

Solution

1. Step 1: Understand named export syntax

   Named exports use the keyword export before the declaration to share multiple items.

2. Step 2: Identify correct syntax for named function export

   The syntax export function calculate() {} correctly exports the function as named export.

3. Final Answer:

   export function calculate() { /*...*/ } -> Option D

4. Quick Check:

   Named export uses export before declaration [OK]

Hint: Use 'export' before function for named export [OK]

Common Mistakes:

• Confusing default export with named export
• Using CommonJS syntax like module.exports
• Using 'export =' which is for different module style

2. Which of the following is the correct syntax to export a constant named PI as the default export in TypeScript?

easy

A. export const default PI = 3.14;

B. const PI = 3.14; export default PI;

C. export default const PI = 3.14;

D. export PI = 3.14;

Solution

1. Step 1: Understand default export syntax

   Default export can export a value or variable by writing export default followed by the value or variable.

2. Step 2: Identify correct way to export constant as default

   We first declare const PI = 3.14; then export it as default using export default PI;.

3. Final Answer:

   const PI = 3.14; export default PI; -> Option B

4. Quick Check:

   Default export uses 'export default' after declaration [OK]

Hint: Declare first, then export default variable [OK]

Common Mistakes:

• Trying to combine 'const' and 'default' in one statement incorrectly
• Using 'export const default' which is invalid
• Confusing named export with default export syntax

3. What will be the output of the following TypeScript code?

export const a = 5;
export const b = 10;

import * as values from './module';
console.log(values.a + values.b);

medium

A. 15

B. undefinedundefined

C. Error: Cannot use import statement outside a module

D. NaN

Solution

1. Step 1: Understand named exports and import * syntax

   The code exports two constants a and b as named exports. The import statement imports all exports as an object named values.

2. Step 2: Calculate the sum of imported values

   Accessing values.a and values.b gives 5 and 10 respectively. Their sum is 15.

3. Final Answer:

   15 -> Option A

4. Quick Check:

   Named exports imported as object sum correctly [OK]

Hint: Import * as object to access all named exports [OK]

Common Mistakes:

• Expecting default export when none is present
• Confusing import syntax causing runtime errors
• Assuming imported values are undefined

4. Identify the error in the following TypeScript export code:

const name = "Alice";
export { name as default };

medium

A. The variable 'name' must be declared with 'export' keyword.

B. The export statement is missing a semicolon.

C. You cannot rename a named export to default in this way.

D. There is no error; this code is correct.

Solution

1. Step 1: Understand export renaming rules

   Renaming exports is allowed, but renaming a named export to default using this syntax is invalid in TypeScript.

2. Step 2: Identify correct way to export default with rename

   To export a variable as default, use export default name; instead of renaming in braces.

3. Final Answer:

   You cannot rename a named export to default in this way. -> Option C

4. Quick Check:

   Default export must use 'export default' syntax [OK]

Hint: Use 'export default' for default export, not rename [OK]

Common Mistakes:

• Trying to rename named export to default inside braces
• Confusing export syntax for default and named exports
• Assuming semicolon omission causes error

5. Given the following module code:

const x = 1;
const y = 2;
const z = 3;

export { x as default, y, z };

Which import statement correctly imports x as default and y and z as named imports?

hard

A. import x, { y, z } from './module';

B. import { default as x, y, z } from './module';

C. import { x, y, z } from './module';

D. import * as all from './module';

Solution

1. Step 1: Understand export renaming and import syntax

   The module exports x renamed as default, and y, z as named exports.

2. Step 2: Identify correct import syntax for default and named exports

   To import default export as x and named exports y, z, use import x, { y, z } from './module';.

3. Final Answer:

   import x, { y, z } from './module'; -> Option A

4. Quick Check:

   Default import first, then named in braces [OK]

Hint: Default import first, named imports in braces [OK]

Common Mistakes:

• Using named import syntax for default export
• Trying to import default as named
• Using import * without destructuring