What this snippet does
Under strict mode, class properties must be initialized in the constructor or have a default value.
Expected output
Compile Error: Property 'x' has no initializer and is not definitely assigned in the constructor.
Why practise typing this
Typing strict compiler flags code builds muscle memory for the symbols and indentation TypeScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
More TypeScript practice
- Initializing properties via the constructorStrict Compiler Flags · intermediate
- Using the definite assignment assertion operatorStrict Compiler Flags · intermediate
- Type-safe usage of callStrict Compiler Flags · intermediate
- Binding a method with correct context and argumentsStrict Compiler Flags · intermediate
- Passing wrong types to call under strict modeStrict Compiler Flags · intermediate
- Declaring an unused variableStrict Compiler Flags · intermediate