Internal: add ApplicativeIdentity to optimize tree shaking

CHANGELOG.md

@@ -13,6 +13,8 @@
 **Note**: Gaps between patch versions are faulty/broken releases. **Note**: A feature tagged as Experimental is in a
 high state of flux, you're at risk of it changing without notice.
 
+# 2.3.10
+
 # 2.3.9
 
 Experimental modules require `fp-ts@^2.5.0`.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "monocle-ts",
-  "version": "2.3.9",
+  "version": "2.3.10",
   "description": "A porting of scala monocle library to TypeScript",
   "main": "lib/index.js",
   "module": "es6/index.js",

src/Traversal.ts

@@ -19,7 +19,6 @@ import * as C from 'fp-ts/lib/Const'
 import { Either } from 'fp-ts/lib/Either'
 import { flow, identity, Predicate, Refinement } from 'fp-ts/lib/function'
 import { HKT, Kind, Kind2, Kind3, URIS, URIS2, URIS3 } from 'fp-ts/lib/HKT'
-import * as I from 'fp-ts/lib/Identity'
 import { Monoid } from 'fp-ts/lib/Monoid'
 import { Option } from 'fp-ts/lib/Option'
 import { pipe } from 'fp-ts/lib/pipeable'
@@ -156,17 +155,14 @@ export const composeOptional: <A, B>(ab: Optional<A, B>) => <S>(sa: Traversal<S,
  * @category combinators
  * @since 2.3.0
  */
-export const modify = <A>(f: (a: A) => A) => <S>(sa: Traversal<S, A>): ((s: S) => S) => {
-  return sa.modifyF(I.identity)(f)
-}
+export const modify = <A>(f: (a: A) => A) => <S>(sa: Traversal<S, A>): ((s: S) => S) =>
+  sa.modifyF(_.ApplicativeIdentity)(f)
 
 /**
  * @category combinators
  * @since 2.3.0
  */
-export const set = <A>(a: A): (<S>(sa: Traversal<S, A>) => (s: S) => S) => {
-  return modify(() => a)
-}
+export const set = <A>(a: A): (<S>(sa: Traversal<S, A>) => (s: S) => S) => modify(() => a)
 
 /**
  * Return a `Traversal` from a `Traversal` focused on a nullable value.

src/internal.ts

@@ -7,7 +7,7 @@
  *
  * @since 2.3.0
  */
-import { Applicative } from 'fp-ts/lib/Applicative'
+import { Applicative, Applicative1 } from 'fp-ts/lib/Applicative'
 import * as RA from 'fp-ts/lib/ReadonlyArray'
 import * as RNEA from 'fp-ts/lib/ReadonlyNonEmptyArray'
 import * as RR from 'fp-ts/lib/ReadonlyRecord'
@@ -25,6 +25,7 @@ import { Prism } from './Prism'
 import { Traversal } from './Traversal'
 import { At } from './At'
 import { NonEmptyArray } from 'fp-ts/lib/NonEmptyArray'
+import { URI as IURI } from 'fp-ts/lib/Identity'
 
 // -------------------------------------------------------------------------------------
 // Iso
@@ -321,6 +322,16 @@ export function traversalComposeTraversal<A, B>(ab: Traversal<A, B>): <S>(sa: Tr
   return (sa) => traversal(<F>(F: Applicative<F>) => (f: (a: B) => HKT<F, B>) => sa.modifyF(F)(ab.modifyF(F)(f)))
 }
 
+/** @internal */
+export const ApplicativeIdentity: Applicative1<IURI> = {
+  URI: 'Identity',
+  map: (fa, f) => f(fa),
+  of: identity,
+  ap:
+    /* istanbul ignore next */
+    (fab, fa) => fab(fa)
+}
+
 /** @internal */
 export function fromTraversable<T extends URIS3>(T: Traversable3<T>): <R, E, A>() => Traversal<Kind3<T, R, E, A>, A>
 /** @internal */