What this snippet does
Fresh object literals are strictly checked for excess properties when directly assigned or passed to functions.
Expected output
Compile Error: Object literal may only specify known properties, and 'y' does not exist in type 'P'.
Why practise typing this
Typing type compatibility 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
- Assigning an object with extra properties to a typeType Compatibility · intermediate
- Structural compatibility between two different classesType Compatibility · intermediate
- Missing required properties in structural typingType Compatibility · intermediate
- Assigning a function with fewer parametersType Compatibility · intermediate
- Using a single argument callback in a mapType Compatibility · intermediate
- Assigning a function with more parametersType Compatibility · intermediate