TypeScript Best Practices 2021. TypeScript(TS) has proven to be a… Quiz

Discover essential TypeScript best practices for writing cleaner, safer, and more maintainable frontend code in 2024. Learn practical strategies to avoid common pitfalls and boost code quality.

1. Correct Data Type Annotation

   Why should you avoid using the 'any' type in TypeScript variable declarations when the data type is known?

   1. It removes the benefits of static type checking and may lead to runtime errors.
   2. It requires more memory for each variable.
   3. It makes the code run slower in browsers.
   4. It automatically converts variable types at runtime.

   Explanation: Using 'any' disables TypeScript's static type checking, increasing the risk of runtime errors due to unexpected values. The other options are incorrect: 'any' does not impact browser execution speed or memory consumption, nor does it perform automatic type conversions.

2. Enabling Strict Mode

   What is the result of enabling the 'strict' configuration in a TypeScript project's tsconfig file?

   1. It makes all variables globally scoped by default.
   2. It enforces stronger type checks and prevents accidental errors.
   3. It increases the speed of code compilation.
   4. It allows the use of undeclared variables.

   Explanation: Enabling 'strict' in tsconfig enforces strict type checking, catching more potential errors at compile time. It does not affect compilation speed or variable scoping, nor does it allow undeclared variables.

3. Using let Instead of var

   Why is 'let' preferred over 'var' when declaring variables in TypeScript?

   1. 'let' does not allow reassignment.
   2. 'let' works only with numbers and strings.
   3. 'let' provides block-level scope and avoids issues with redeclaration.
   4. 'let' makes variables global by default.

   Explanation: 'let' creates variables scoped to the nearest block and prevents redeclaration in the same scope, making code more predictable. The other options are incorrect: 'let' is not limited by type, does not make variables global, and still allows variable reassignment.

4. Choosing const for Constants

   What is a key characteristic of variables declared with 'const' in TypeScript?

   1. Their values cannot be reassigned after declaration.
   2. Their values can change but only within functions.
   3. They automatically become properties of window.
   4. They can be redeclared in the same scope.

   Explanation: 'const' variables cannot be reassigned, providing immutability for primitives. They are not automatically global, cannot be redeclared in the same scope, and their assignment rules do not change in functions.

5. Using Tuples for Fixed-Length Data

   When should a tuple be used instead of a regular array in TypeScript?

   1. When you want dynamic typing for each element.
   2. When the array length will change frequently.
   3. When all elements will always be of the same type.
   4. When the array should have a fixed length and specific data types at each position.

   Explanation: Tuples provide fixed length and defined types at each index, improving safety for structured data. Regular arrays allow variable length and element types but do not enforce positional type safety. The other options describe use cases better suited for regular arrays, not tuples.