rustie-ts

TypeScript library with helper types and functions to type-safely handle Rust's
serde JSON serialization of enums.

rustie can also be used standalone to implement enums/tagged-unions in
TypeScript with plain objects.

Installation

``sh
npm install --save rustie


OR


yarn add rustie
`

Example

`ts
import type { Enum } from "."
import { extract_variant, match, if_let } from "."

type Event = Enum<{
Ping: null
KeyPress: { key: string }
Click: { x: number; y: number }
}>

const a = { Click: { x: 10, y: 20 } }
const b = { KeyPress: { key: "a" } }
const c = { Ping: null }

const events: Event[] = [a, b, c]

// == Matching with 'match' function ==

for (const elem of events) {
match(elem)({
Click: ({ x, y }) => console.log(Click at ${x}, ${y}),
KeyPress: ({ key }) => console.log(Key pressed: ${key}),
Ping: () => console.log(Ping!),
})
}

// == Matching with 'if_let' function ==

for (const elem of events) {
if_let(elem, "Click")(
(color) => console.log(This is click: X:${color.x} Y:${color.y}),
(x) => console.log(This is not click:, x)
)
}

// == Matching with extract_variant function ==

for (const elem of events) {
const variant = extract_variant(elem)
switch (variant.$) {
case "Click":
const click = variant.val
console.log(Click at ${click.x}, ${click.y})
// console.log(${click.key}) // Type check FAILS
break
case "KeyPress":
const key_press = variant.val
console.log(Key pressed: ${key_press.key})
// console.log(${key_press.x}) // Type check FAILS
break
case "Ping":
console.log(Ping!)
break
}
}

// == Overlapping else ==

type Status = Enum<{
Ok: null
Warn: { message: string }
Err: { message: string }
}>

const statuses: Status[] = [{ Ok: null }, { Err: { message: "Error" } }]

for (const status of statuses) {
if_let(status, "Ok")(
() => console.log("This is Ok"), // Runs only on Ok
({ message }) => console.log(This is not Ok: ${message}) // Runs on Warn and Err
)
}

// == Typing Results ==

for (const event of events) {
const result = match(event)({
Click: ({ x, y }) => x + y,
KeyPress: ({ key }) => key,
Ping: () => "pong",
})
const result2 = match(event)({
Click: ({ x, y }): number | string => x + y,
KeyPress: ({ key }) => key,
Ping: () => "pong",
})
}
``