0.1.4 (#5)

Co-authored-by: Julien Valverdé <julien.valverde@mailo.com>
Reviewed-on: Thilawyn/effect-fc#5

packages/effect-fc/src/PropertyPath.ts

@@ -0,0 +1,98 @@
+import { Array, Equivalence, Function, Option, Predicate } from "effect"
+
+
+export type PropertyPath = readonly PropertyKey[]
+
+type Prev = readonly [never, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+export type Paths<T, D extends number = 5, Seen = never> = readonly [] | (
+    D extends never ? readonly [] :
+    T extends Seen ? readonly [] :
+    T extends readonly any[] ? {
+        [K in keyof T as K extends number ? K : never]:
+            | readonly [K]
+            | readonly [K, ...Paths<T[K], Prev[D], Seen | T>]
+    } extends infer O
+        ? O[keyof O]
+        : never
+    :
+    T extends object ? {
+        [K in keyof T as K extends string | number | symbol ? K : never]-?:
+            NonNullable<T[K]> extends infer V
+                ? readonly [K] | readonly [K, ...Paths<V, Prev[D], Seen>]
+                : never
+    } extends infer O
+        ? O[keyof O]
+        : never
+    :
+    never
+)
+
+export type ValueFromPath<T, P extends readonly any[]> = P extends readonly [infer Head, ...infer Tail]
+    ? Head extends keyof T
+        ? ValueFromPath<T[Head], Tail>
+        : T extends readonly any[]
+            ? Head extends number
+                ? ValueFromPath<T[number], Tail>
+                : never
+            : never
+    : T
+
+
+export const equivalence: Equivalence.Equivalence<PropertyPath> = Equivalence.array(Equivalence.strict())
+
+export const unsafeGet: {
+    <T, const P extends Paths<T>>(path: P): (self: T) => ValueFromPath<T, P>
+    <T, const P extends Paths<T>>(self: T, path: P): ValueFromPath<T, P>
+} = Function.dual(2, <T, const P extends Paths<T>>(self: T, path: P): ValueFromPath<T, P> =>
+    path.reduce((acc: any, key: any) => acc?.[key], self)
+)
+
+export const get: {
+    <T, const P extends Paths<T>>(path: P): (self: T) => Option.Option<ValueFromPath<T, P>>
+    <T, const P extends Paths<T>>(self: T, path: P): Option.Option<ValueFromPath<T, P>>
+} = Function.dual(2, <T, const P extends Paths<T>>(self: T, path: P): Option.Option<ValueFromPath<T, P>> =>
+    path.reduce(
+        (acc: Option.Option<any>, key: any): Option.Option<any> => Option.isSome(acc)
+            ? Predicate.hasProperty(acc.value, key)
+                ? Option.some(acc.value[key])
+                : Option.none()
+            : acc,
+
+        Option.some(self),
+    )
+)
+
+export const immutableSet: {
+    <T, const P extends Paths<T>>(path: P, value: ValueFromPath<T, P>): (self: T) => Option.Option<T>
+    <T, const P extends Paths<T>>(self: T, path: P, value: ValueFromPath<T, P>): Option.Option<T>
+} = Function.dual(3, <T, const P extends Paths<T>>(self: T, path: P, value: ValueFromPath<T, P>): Option.Option<T> => {
+    const key = Array.head(path as PropertyPath)
+    if (Option.isNone(key))
+        return Option.some(value as T)
+    if (!Predicate.hasProperty(self, key.value))
+        return Option.none()
+
+    const child = immutableSet<any, any>(self[key.value], Option.getOrThrow(Array.tail(path as PropertyPath)), value)
+    if (Option.isNone(child))
+        return child
+
+    if (Array.isArray(self))
+        return typeof key.value === "number"
+            ? Option.some([
+                ...self.slice(0, key.value),
+                child.value,
+                ...self.slice(key.value + 1),
+            ] as T)
+            : Option.none()
+
+    if (typeof self === "object")
+        return Option.some(
+            Object.assign(
+                Object.create(Object.getPrototypeOf(self)),
+                { ...self, [key.value]: child.value },
+            )
+        )
+
+    return Option.none()
+})