pheno

Simple, lightweight at-runtime type checking functions, with full TypeScript support

Features

- Full TypeScript integration: TypeScript understands that assertType and isOfType narrow the types of things, and will refine them accordingly
- Simple: Type validators are just functions that return booleans.
- Effective: There's lots of utility functions that help you represent all the various types you'd care about in your code.
- Lightweight: The whole library is 21K minified (5.0K gzipped, 4.4K brotli-ified), but can be even smaller if your bundler supports tree-shaking.

Usage Example

``ts
import * as types from "pheno";

function something(first: unknown, second: unknown) {
// Throws an error if first is not a string
types.assertType(first, types.string);

// Throws an error if second is not string | number
types.assertType(second, types.union(types.string, types.number));

// Typescript now knows that first is a string and second is string | number
return first + " " + String(second);
}
`

List of types and type builder functions

- and
- any
- anyArray
- anyFunction
- anyMap
- anyObject
- anySet
- anyTypeValidator
- array (alias of arrayOfUnknown)
- arrayOf
- arrayOfAny
- arrayOfUnknown
- Array (alias of arrayOfUnknown)
- assertType (assert that a value has the provided type, and throw an error message if it doesn't)
- asType (do a TypeScript as cast to convert the value into the provided type)
- bigint
- BigInt (alias of bigint)
- boolean
- Boolean (alias of boolean)
- Date
- Error
- exactBigInt
- exactNumber
- exactString
- exactSymbol
- false
- falsy
- Function (alias of unknownFunction)
- hasClassName
- hasToStringTag
- Infinity
- instanceOf
- integer
- intersection
- isOfType (return a boolean indicating if a value is of the provided type)
- map (alias of unknownMap)
- Map (alias of unknownMap)
- mapOf
- mappingObjectOf
- maybe
- NaN
- NegativeInfinity
- never
- nonNullOrUndefined
- null
- nullish
- void (alias of nullish)
- number (doesn't include NaN, Infinity, or -Infinity)
- Number (alias of number)
- numberIncludingNanAndInfinities
- object (alias of unknownObject)
- Object (alias of unknownObject)
- objectOrNull
- objectWithOnlyTheseProperties
- objectWithProperties
- or
- optional
- partialObjectWithProperties
- record
- RegExp
- set (alias of unknownSet)
- Set (alias of unknownSet)
- setOf
- string
- String (alias of string)
- stringifyValue (safe and lightweight value-to-string function, for printing values in error messages)
- stringMatching
- Symbol
- symbol (alias of Symbol)
- symbolFor
- true
- truthy
- tuple
- undefined
- union
- unknown
- unknownFunction
- unknownMap
- unknownObject
- unknownSet
- unknownTypeValidator
- ArrayBuffer
- SharedArrayBuffer
- DataView
- TypedArray
- Int8Array
- Uint8Array
- Uint8ClampedArray
- Int16Array
- Uint16Array
- Int32Array
- Uint32Array
- Float32Array
- Float64Array`

Please see the TypeScript types for each of these in either your editor's autocomplete or pheno's source code for more information.

License

MIT