Collection Literals

Collection If

Conditional Element

An if (cond) value inside a literal includes the value only when the condition is true.

Program

Play the program to include a bonus element when a flag is on.

collection_if.dart
Replay: real traced execution (multi-file project)
void main() {
  var includeBonus = true;
  var items = ['a', 'b', if (includeBonus) 'bonus'];
  print(items);
}

  1. includeBonus ← true

    1void main() {2  var includeBonus = true;3  var items = ['a', 'b', if (includeBonus) 'bonus'];
    values this steptrueincludeBonus

  2. items ← [a, b, bonus]

    2var includeBonus = true;3var items = ['a', 'b', if (includeBonus) 'bonus'];4print(items);
    values this step[a, b, bonus]itemstrueincludeBonus

  3. print(items);

    3  var items = ['a', 'b', if (includeBonus) 'bonus'];4  print(items);5}
    output[a, b, bonus]
    values this step[a, b, bonus]items
collection-if `if (cond) value` lives inside a list/set/map literal.
inline branching Avoids building the list and patching it later.
clarity Reads like the data layout itself.