What this snippet does
Under strict mode, array methods like find return T | undefined, forcing the developer to check for undefined before use.
Expected output
Compile Error: Object is possibly 'undefined'.
Why practise typing this
Typing tsconfig & compiler 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
- Enabling strict mode in tsconfigtsconfig & Compiler · intermediate
- Implicit any in function parameters under stricttsconfig & Compiler · intermediate
- Preventing null assignment to stringstsconfig & Compiler · intermediate
- Checking for null before accessing propertiestsconfig & Compiler · intermediate
- Array index access returns T instead of T | undefinedtsconfig & Compiler · intermediate
- Catching implicit any in variablestsconfig & Compiler · intermediate