packages/effect-fc/src/Lens.ts

@@ -41,13 +41,12 @@ extends Pipeable.Class() implements Lens<A, ER, RR, EW, RW> {
 
 export const isLens = (u: unknown): u is Lens<unknown, unknown, unknown, unknown, unknown> => Predicate.hasProperty(u, LensTypeId)
 
-export const make = <A, ER, RR, EW, RW>(
-    options: {
+
+export const make = <A, ER, RR, EW, RW>(options: {
     readonly get: Effect.Effect<A, ER, RR>
     readonly changes: Stream.Stream<A, ER, RR>
     readonly set: (a: A) => Effect.Effect<void, EW, RW>
-    }
-): Lens<A, ER, RR, EW, RW> => new LensImpl(options.get, options.changes, options.set)
+}): Lens<A, ER, RR, EW, RW> => new LensImpl(options.get, options.changes, options.set)
 
 /**
  * Creates a `Lens` that directly proxies a `SubscriptionRef`.
@@ -60,6 +59,51 @@ export const fromSubscriptionRef = <A>(
     set: a => SubscriptionRef.set(ref, a),
 })
 
+
+export const map = <A, ER, RR, EW, RW, B>(
+    self: Lens<A, ER, RR, EW, RW>,
+    get: (a: A) => B,
+    set: (b: B) => A,
+): Lens<B, ER, RR, EW, RW> => {
+    make({
+        get: Effect.map(self.get, get),
+        changes: Stream.map(self.changes, get),
+
+    })
+    const get = Effect.map(self.get, f)
+    const changes = Stream.map(self.changes, f)
+    const set = (b: B) => self.set(g(b))
+
+    const out = new LensImpl(get, changes, set)
+
+    ;(out as any).modify = <C, E1 = never, R1 = never>(
+        h: (b: B) => Effect.Effect<readonly [C, B], E1, R1>
+    ) => self.modify((a: A) => {
+        const b = f(a)
+        return Effect.flatMap(h(b), ([c, bNext]) => Effect.succeed([c, g(bNext)] as const))
+    })
+
+    return out
+}
+
+export const mapEffect = <A, ER, RR, EW, RW, B, EGet = never, RGet = never, ESet = never, RSet = never>(
+    self: Lens<A, ER, RR, EW, RW>,
+    getF: (a: A) => Effect.Effect<B, EGet, RGet>,
+    setF: (b: B) => Effect.Effect<A, ESet, RSet>,
+): Lens<B, ER | EGet, RR | RGet, EW | ESet, RW | RSet> => {
+    const get = Effect.flatMap(self.get, getF)
+    const changes = Stream.mapEffect(self.changes, getF)
+    const set = (b: B) => Effect.flatMap(setF(b), a => self.set(a))
+
+    const out = new LensImpl(get, changes, set)
+
+    ;(out as any).modify = <C, E1 = never, R1 = never>(
+        h: (b: B) => Effect.Effect<readonly [C, B], E1, R1>
+    ) => self.modify((a: A) => Effect.flatMap(getF(a), b => Effect.flatMap(h(b), ([c, bNext]) => Effect.flatMap(setF(bNext), nextA => Effect.succeed([c, nextA] as const)))))
+
+    return out
+}
+
 export const unwrap = <A, ER, RR, EW, RW, E1, R1>(
     effect: Effect.Effect<Lens<A, ER, RR, EW, RW>, E1, R1>
 ): Lens<A, ER | E1, RR | R1, EW | E1, RW | R1> => make({