Instruction: Explain how TypeScript treats null and undefined values, including any configuration options that affect their handling.
Context: This question examines the candidate's knowledge of TypeScript's type system, specifically its treatment of null and undefined values.
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TypeScript, with its robust type system, provides a comprehensive way to deal with null and undefined values, enhancing JavaScript's capabilities and ensuring type safety. By default, TypeScript treats null and undefined as distinct types. This means variables declared with a certain type cannot be assigned null or undefined unless explicitly specified.
For example, if we declare a variable as a number, assigning null or undefined to this variable would result in a compilation error unless we tell TypeScript that such values are acceptable. This is where the strictNullChecks compiler option comes into play. When strictNullChecks is enabled, which I highly recommend for most projects to catch null-reference errors early, TypeScript enforces strict null checking. This means that you must explicitly annotate...