D
Dart LanguageBeginner10 XP3 min read

What are named, positional, and required parameters in Dart?

TL;DR: Positional parameters are passed by position; named parameters are passed by name (in braces); required keyword makes named parameters mandatory; optional positional params use [] with defaults.

Full Answer

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Flutter widget constructors use named parameters extensively because widgets can have many properties. Required named parameters give you compile-time safety — you must provide them.

Code Examples

dartAll parameter types
Output
[INFO] Hello
[ERR] Error!
Bob, 0
Alice, 25

Interview Tip

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Flutter's const constructor pattern always uses named parameters with required. This allows the compiler to verify all required data is passed at compile time, not runtime.

#parameters#named#positional#required#optional