Summary - Packages
- Dart course
- Intermediate
- Lesson 99/116
- 5 min
Combine pubspec, pub get and import to set up a package structure.
Summary: Packages
In this group you saw the pub commands, the pubspec.yaml structure, dart pub get, the import statement and dart pub publish. Packages are the foundation of the Dart ecosystem.
Now we combine them: we will import the dart:math and dart:convert libraries and turn a Map into JSON.
Remember: pubspec lists dependencies; pub get fetches; import uses; publish publishes.
Practice max and min JSON
Import the libraries with import 'dart:math'; and import 'dart:convert';. In main pass the Map {'max': max(3, 7), 'min': min(3, 7)} to jsonEncode inside print.
Starter code
// Import the dart:math and dart:convert libraries
void main() {
// print a Map with max and min using jsonEncode
}Sample solution
import 'dart:math';
import 'dart:convert';
void main() {
print(jsonEncode({'max': max(3, 7), 'min': min(3, 7)}));
}Expected output
{"max":7,"min":3}
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Concept matching
| Term | Meaning |
|---|---|
pub |
Package manager |
pubspec.yaml |
Configuration |
dart pub get |
Fetching |
import |
Importing |
2 When is dart pub get run?
- When publishing
- When dependencies change Correct answer
- When writing tests
- When defining a class
Explanation: pub get is run when dependencies change.
3 The import statement
____ 'dart:math';import 'dart:math';Explanation: a library is imported with import.