replace chain with flatMap when possible

Do.md

@@ -38,6 +38,6 @@ const nameDo: T.Task<void> = pipe(
   T.chainFirst(() => putStrLn('And your last name? ')),
   T.bind('last', () => getLine),
   T.bind('full', ({ first, last }) => T.of(first + ' ' + last)),
-  T.chain(({ full }) => putStrLn('Pleased to meet you, ' + full + '!'))
+  T.flatMap(({ full }) => putStrLn('Pleased to meet you, ' + full + '!'))
 )
 ```

docs/modules/Either.ts.md

@@ -54,7 +54,7 @@ export const functional = (as: ReadonlyArray<number>): string => {
     as,
     head,
     E.map(double),
-    E.chain(inverse),
+    E.flatMap(inverse),
     E.match(
       (err) => `Error is ${err}`, // onLeft handler
       (head) => `Result is ${head}` // onRight handler

docs/modules/IORef.ts.md

@@ -51,10 +51,10 @@ export declare class IORef<A> {
 **Example**
 
 ```ts
-import { io } from 'fp-ts/IO'
+import { flatMap } from 'fp-ts/IO'
 import { newIORef } from 'fp-ts/IORef'
 
-assert.strictEqual(io.chain(newIORef(1), (ref) => io.chain(ref.write(2), () => ref.read))(), 2)
+assert.strictEqual(flatMap(newIORef(1), (ref) => flatMap(ref.write(2), () => ref.read))(), 2)
 ```
 
 Added in v2.0.0

docs/modules/Option.ts.md

@@ -52,7 +52,7 @@ export const functional = (as: ReadonlyArray<number>): string => {
     as,
     head,
     O.map(double),
-    O.chain(inverse),
+    O.flatMap(inverse),
     O.match(
       () => 'no result', // onNone handler
       (head) => `Result is ${head}` // onSome handler

src/Either.ts

@@ -47,7 +47,7 @@
  *     as,
  *     head,
  *     E.map(double),
- *     E.chain(inverse),
+ *     E.flatMap(inverse),
  *     E.match(
  *       (err) => `Error is ${err}`, // onLeft handler
  *       (head) => `Result is ${head}` // onRight handler

src/IOEither.ts

@@ -891,20 +891,7 @@ export const bracketW: <E1, A, E2, B, E3>(
   use: (a: A) => IOEither<E2, B>,
   release: (a: A, e: E.Either<E2, B>) => IOEither<E3, void>
 ) => IOEither<E1 | E2 | E3, B> = (acquire, use, release) =>
-  pipe(
-    acquire,
-    chainW((a) =>
-      pipe(
-        use(a),
-        I.chain((e) =>
-          pipe(
-            release(a, e),
-            chainW(() => I.of(e))
-          )
-        )
-      )
-    )
-  )
+  flatMap(acquire, (a) => I.flatMap(use(a), (e) => flatMap(release(a, e), () => I.of(e))))
 
 // -------------------------------------------------------------------------------------
 // do notation

src/IORef.ts

@@ -7,10 +7,10 @@ import { IO } from './IO'
 
 /**
  * @example
- * import { io } from 'fp-ts/IO'
+ * import { flatMap } from 'fp-ts/IO'
  * import { newIORef } from 'fp-ts/IORef'
  *
- * assert.strictEqual(io.chain(newIORef(1), ref => io.chain(ref.write(2), () => ref.read))(), 2)
+ * assert.strictEqual(flatMap(newIORef(1), ref => flatMap(ref.write(2), () => ref.read))(), 2)
  *
  * @category model
  * @since 2.0.0

src/Option.ts

@@ -46,7 +46,7 @@
  *     as,
  *     head,
  *     O.map(double),
- *     O.chain(inverse),
+ *     O.flatMap(inverse),
  *     O.match(
  *       () => 'no result', // onNone handler
  *       (head) => `Result is ${head}` // onSome handler

src/TaskEither.ts

@@ -1259,20 +1259,7 @@ export const bracketW: <E1, A, E2, B, E3>(
   use: (a: A) => TaskEither<E2, B>,
   release: (a: A, e: E.Either<E2, B>) => TaskEither<E3, void>
 ) => TaskEither<E1 | E2 | E3, B> = (acquire, use, release) =>
-  pipe(
-    acquire,
-    chainW((a) =>
-      pipe(
-        use(a),
-        T.chain((e) =>
-          pipe(
-            release(a, e),
-            chainW(() => T.of(e))
-          )
-        )
-      )
-    )
-  )
+  flatMap(acquire, (a) => T.flatMap(use(a), (e) => flatMap(release(a, e), () => T.of(e))))
 
 // -------------------------------------------------------------------------------------
 // do notation