ts-reflection
Type inspection utilities for TypeScript
ts-reflection
allows you to access information about your types in runtime - e.g. get properties of a type or possible values of a union. It is compatible with rollup, webpack, and ttypescript projects and works nicely with jest or ts-node
Motivation | API | Installation | Acknowledgement
Wait what?
As they say an example is worth a thousand API docs so why not start with one.
; // You can now use propertiesOf utility to get properties of a type; // ['name', 'hobbies']
Let's do another one!
; ; // You can use valuesOf utility to get all the possible union type values; // ['primary', 'secondary', 'link']
Motivation
I can't count the number of times I needed to type all the possible values of a union type to create e.g. a dropdown with all the button types:
; ;
I was always aware of fragility of such solution and the fact you need to update it by hand every time ButtonType
changes. Now I can write just
;
The same goes for a list of type properties - typing those lists of keyof
type values:
;
Which now becomes
;
API
You can find comprehensive API documentation in the API docs.
ts-reflection
exports two functions: valuesOf
(for accessing values of union types) and propertiesOf
(for accessing properties of types).
valuesOf
valuesOf
is a function that returns all the possible literal values of union types:
; ; // You can use valuesOf utility to get all the possible union type values; // ['string value', 1, true, Symbol.toStringTag]
Please read the full API docs for more information about valuesOf
.
propertiesOf
propertiesOf
is a function that returns property names of types:
; // When called with no arguments, propertiesOf() returns all public properties of a type; // ['name', 'displayName', 'hobbies'] // You can also call it with "queries" to be more specific about what properties you want to get; // ['hobbies']; // ['name', 'displayName']; // ['displayName']; // ['name', 'hobbies']
Please read the full API docs for more information about propertiesOf
and the queries it supports.
Installation
You can find comprehensive installation instructions in the installation docs.
Acknowledgement
This idea was inspired by ts-transformer-keys
NPM module. The E2E testing infrastructure that ensures compatibility with all minor TypeScript versions is based on my ts-type-checked
project.