From 35b1bb4da573b13db70fdfda6425ebea60427d7f Mon Sep 17 00:00:00 2001
From: "Sahar Rachamim (Kishu)" <srachamim@gmail.com>
Date: Tue, 13 Oct 2020 15:26:27 +0300
Subject: [PATCH] Add description & example to sequence in Either

---
 docs/modules/Either.ts.md | 14 ++++++++++++++
 src/Either.ts             | 17 +++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/docs/modules/Either.ts.md b/docs/modules/Either.ts.md
index 1500cee4b..1a42b0f1b 100644
--- a/docs/modules/Either.ts.md
+++ b/docs/modules/Either.ts.md
@@ -440,12 +440,26 @@ Added in v2.6.3
 
 ## sequence
 
+Evaluate each monadic action in the structure from left to right, and collect the results.
+
 **Signature**
 
 ```ts
 export declare const sequence: Sequence2<'Either'>
 ```
 
+**Example**
+
+```ts
+import { pipe } from 'fp-ts/function'
+import * as E from 'fp-ts/Either'
+import * as O from 'fp-ts/Option'
+
+assert.deepStrictEqual(pipe(E.right(O.some('a')), E.sequence(O.option)), O.some(E.right('a')))
+
+assert.deepStrictEqual(pipe(E.right(O.none), E.sequence(O.option)), O.none)
+```
+
 Added in v2.6.3
 
 ## traverse
diff --git a/src/Either.ts b/src/Either.ts
index 15a69b271..4ff612ade 100644
--- a/src/Either.ts
+++ b/src/Either.ts
@@ -617,6 +617,23 @@ export const traverse: PipeableTraverse2<URI> = <F>(F: ApplicativeHKT<F>) => <A,
 ): HKT<F, Either<E, B>> => (isLeft(ta) ? F.of(left(ta.left)) : F.map<B, Either<E, B>>(f(ta.right), right))
 
 /**
+ * Evaluate each monadic action in the structure from left to right, and collect the results.
+ *
+ * @example
+ * import { pipe } from 'fp-ts/function'
+ * import * as E from 'fp-ts/Either'
+ * import * as O from 'fp-ts/Option'
+ *
+ * assert.deepStrictEqual(
+ *   pipe(E.right(O.some('a')), E.sequence(O.option)),
+ *   O.some(E.right('a')),
+ *  )
+ *
+ * assert.deepStrictEqual(
+ *   pipe(E.right(O.none), E.sequence(O.option)),
+ *   O.none
+ * )
+ *
  * @category Traversable
  * @since 2.6.3
  */