TypeScript Financial Management & Budgeting 3

Question 1

A TypeScript budget API returns `Promise<Transaction[]>`. When fetching with `async/await`, what is the correct type of the resolved variable?

Accepted Answer

Transaction[]

Answer

Awaiting a `Promise` yields type `T`, so awaiting `Promise` gives `Transaction[]`.

Question 2

You want to prevent accidental mutation of a budget plan object in TypeScript. Which approach makes ALL nested properties immutable at the type level?

Accepted Answer

DeepReadonly<BudgetPlan> via a custom recursive type

Answer

Built-in `Readonly` only makes top-level properties readonly; a recursive `DeepReadonly` type is needed for full deep immutability.

Question 3

Which TypeScript compiler option would catch an uninitialized `totalBudget` variable before it's used in a calculation?

Accepted Answer

strictPropertyInitialization

Answer

`strictPropertyInitialization` ensures class properties are assigned in the constructor, catching uninitialized state at compile time.

Question 4

A financial service class has a private `_balance: number`. TypeScript access modifiers are:

Accepted Answer

Only a compile-time concept with no runtime enforcement

Answer

TypeScript's `private`, `protected`, and `public` modifiers are erased at compilation; the emitted JavaScript has no access restrictions.

Question 5

You need a TypeScript function that calculates tax differently based on income bracket. Which technique allows different parameter and return type combinations for the same function name?

Accepted Answer

Function overloads

Answer

Function overloads let you declare multiple signatures for a function, enabling different input/output type pairs for the same function.

TypeScript Practice Test

TypeScript Practice Test

TypeScript Financial Management & Budgeting 3