Type Predicates
Understand how Type Predicates work in TypeScript, using an example of filtering a mixed array of elements.
More Tips
Play TypeScript 5.1 Beta is OUT!
TypeScript 5.1 Beta is OUT!
2 mins
Play How to Name your Types
How to Name your Types
4 mins
Play Don't use return types, unless...
Don't use return types, unless...
4 mins
Play TypeScript 5.0 Beta Deep Dive
TypeScript 5.0 Beta Deep Dive
6 mins
Play Conform a Derived Type Without Losing Its Literal Values
Conform a Derived Type Without Losing Its Literal Values
1 min
Play Avoid unexpected behavior of React’s useState
Avoid unexpected behavior of React’s useState
1 min
Play Understand assignability in TypeScript
Understand assignability in TypeScript
2 mins
Play Compare function overloads and generics
Compare function overloads and generics
1 min
Play Use infer in combination with string literals to manipulate keys of objects
Use infer in combination with string literals to manipulate keys of objects
1 min
Play Access deeper parts of objects and arrays
Access deeper parts of objects and arrays
1 min
Play Ensure that all call sites must be given value
Ensure that all call sites must be given value
1 min
Play Understand how TypeScript infers literal types
Understand how TypeScript infers literal types
1 min
Play Get a TypeScript package ready for release to NPM in under 2 minutes
Get a TypeScript package ready for release to NPM in under 2 minutes
1 min
Play Use assertion functions inside classes
Use assertion functions inside classes
1 min
Play Assign local variables to default generic slots to dry up your code and improve performance
Assign local variables to default generic slots to dry up your code and improve performance
2 mins
Play Know when to use generics
Know when to use generics
2 mins
Play Map over a union type
Map over a union type
1 min
Play Make accessing objects safer by enabling 'noUncheckedIndexedAccess' in tsconfig
Make accessing objects safer by enabling 'noUncheckedIndexedAccess' in tsconfig
1 min
Play Use generics to dynamically specify the number, and type, of arguments to functions
Use generics to dynamically specify the number, and type, of arguments to functions
1 min
Play Use 'declare global' to allow types to cross module boundaries
Use 'declare global' to allow types to cross module boundaries
2 mins
Play Turn a module into a type
Turn a module into a type
2 mins
Play Create autocomplete helper which allows for arbitrary values
Create autocomplete helper which allows for arbitrary values
2 mins
Play Use deep partials to help with mocking an entity
Use deep partials to help with mocking an entity
1 min
Play Throw detailed error messages for type checks
Throw detailed error messages for type checks
1 min
Play Create a 'key remover' function which can process any generic object
Create a 'key remover' function which can process any generic object
1 min
Play Use generics in React to make dynamic and flexible components
Use generics in React to make dynamic and flexible components
1 min
Play Create your own 'objectKeys' function using generics and the 'keyof' operator
Create your own 'objectKeys' function using generics and the 'keyof' operator
1 min
Play Write your own 'PropsFrom' helper to extract props from any React component
Write your own 'PropsFrom' helper to extract props from any React component
1 min
Play Use 'extends' keyword to narrow the value of a generic
Use 'extends' keyword to narrow the value of a generic
1 min
Play Use function overloads and generics to type a compose function
Use function overloads and generics to type a compose function
2 mins
Play Decode URL search params at the type level with ts-toolbelt
Decode URL search params at the type level with ts-toolbelt
2 mins
Play Use 'in' operator to transform a union to another union
Use 'in' operator to transform a union to another union
2 mins
Play Derive a union type from an object
Derive a union type from an object
2 mins