TypeScript Tricks

Type System

TS Non-Nullable Types

Non-Nullable Types

TypeScript non-nullable types enforce strictNullChecks reducing null errors.

Introduction to Non-Nullable Types

In TypeScript, non-nullable types are a powerful feature that help developers avoid null and undefined errors. By default, TypeScript allows null and undefined as valid values for all types. However, this can lead to runtime errors if not handled properly. With non-nullable types, you can enforce stricter type checking, reducing the chances of encountering null-related issues.

Enabling Strict Null Checks

To leverage non-nullable types, you need to enable the strictNullChecks option in your tsconfig.json file. This option ensures that null and undefined are not assignable to any other types unless explicitly stated using union types.

Handling Null and Undefined

When strictNullChecks is enabled, TypeScript enforces that variables can only be null or undefined if their type explicitly allows it. This is done using union types, such as string | null or number | undefined.

Non-Nullable Type Operator

TypeScript provides a non-null assertion operator (!) that can be used when you know a value cannot be null or undefined, but the compiler cannot guarantee it. This operator tells TypeScript to ignore the possibility of null or undefined for that expression.

Best Practices with Non-Nullable Types

  • Enable strictNullChecks in your TypeScript projects for safer code.
  • Use union types to explicitly allow null or undefined where necessary.
  • Avoid using the non-null assertion operator unless absolutely sure of the value's existence.

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