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49th Week of 2021

Computer Science⚑

CICD⚑

Github Actions⚑

  • New: Concurrency.

    You can use concurrency to cancel any in-progress job or run. Example:

    concurrency:
  group: docs-${{ github.head_ref }}
  cancel-in-progress: true

    This is useful to cancel previous jobs if new commits are pushed, which saves minutes, energy and avoids conflicts when pushing changes during the action.

Programming⚑

Basics⚑

  • New: Add Flutter basics about maps.
  • New: Writing Flutter documentation.

  • New: Combine/merge/concat maps.

    You can use spread operator ...:

    final firstMap = {"1":"2"};
final secondMap = {"2":"3"};

final thirdMap = {
   ...firstMap,
   ...secondMap,
};

  • New: Find element from list.

    Use .firstWhere():

    List<Currency> currencies = ...;
Currency dollar = currencies.firstWhere((currency) => currency.code == "USD");

  • New: .? operator.

    Use ?. when you want to call a method/getter on an object if that object is not null (otherwise, return null).

    Example:

    currentState?.open();

Debugging⚑

  • New: Debugging Flutter.

    Import dart:developer and add debugger(); wherever you want. Then, open your browsers developer tools and use the console.

pytest⚑

  • New: Class fixture.

    To run a custom function for every test in a class do:

    class TestClass:
    @pytest.fixture(autouse=True)
    def setup(self):
        self.variable = 42

    def test_something(self):
        ...

Other⚑

  • New: Catch only some kind of errors.

    Use @retry(retry=retry_if_exception_type(IOError)).

    Several types of exceptions can be combined as follows:

    @retry(retry=(retry_if_exception_type(IOError) | retry_if_exception_type(TimeoutError)))

  • New: Parse hexadecimal color string.

    /// Construct a color from a hex code string, of the format #RRGGBB.
Color hexToColor(String code) {
  return new Color(int.parse(code.substring(1, 7), radix: 16) + 0xFF000000);
}