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Dart Chapter 6 of 15

Null Safety

Understand nullable and non-nullable types, the null-aware operators, and late variables, so null errors are caught before your code runs.

In many languages the most common crash is using a value that turned out to be missing. Dart’s type system rules that out. This chapter is short, but it changes how you write every line.

Lessons in this chapter

  1. Null Safety in Dart: Nullable and Non-Nullable TypesLearn sound null safety in Dart: what null is, nullable types with ?, type promotion, and how the compiler prevents null errors.
  2. Null-Aware Operators in Dart: ?., ??, ??= and !Learn Dart's null-aware operators with examples: safe access with ?., default values with ??, assign-if-null with ??= and the ! assertion.
  3. The late Keyword in Dart: Late and Lazy InitializationLearn when and how to use the late keyword in Dart for variables initialized after declaration, and for lazy initialization.