From 5ea1bfe780a305c0600190084b36f1967c0b3857 Mon Sep 17 00:00:00 2001
From: Justin Ridgewell <justin@ridgewell.name>
Date: Sat, 3 Feb 2018 17:08:12 -0500
Subject: [PATCH] Do not optimize away async/gen arrow functions (#7319)

* Do not optimize away async/gen arrow functions

* Node version 8
---
 .../src/index.js                                    |  5 ++++-
 .../fixtures/pipeline-operator/async-arrow/exec.js  | 13 +++++++++++++
 .../fixtures/pipeline-operator/async-arrow/input.js | 13 +++++++++++++
 .../pipeline-operator/async-arrow/options.json      |  3 +++
 .../pipeline-operator/async-arrow/output.js         | 12 ++++++++++++
 5 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/exec.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/input.js
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/options.json
 create mode 100644 packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/output.js

diff --git a/packages/babel-plugin-proposal-pipeline-operator/src/index.js b/packages/babel-plugin-proposal-pipeline-operator/src/index.js
index 758211975b..e96bd2231a 100644
--- a/packages/babel-plugin-proposal-pipeline-operator/src/index.js
+++ b/packages/babel-plugin-proposal-pipeline-operator/src/index.js
@@ -14,7 +14,10 @@ export default function() {
         if (operator !== "|>") return;
 
         let optimizeArrow =
-          t.isArrowFunctionExpression(right) && t.isExpression(right.body);
+          t.isArrowFunctionExpression(right) &&
+          t.isExpression(right.body) &&
+          !right.async &&
+          !right.generator;
         let param;
 
         if (optimizeArrow) {
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/exec.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/exec.js
new file mode 100644
index 0000000000..648a737a53
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/exec.js
@@ -0,0 +1,13 @@
+function then(fn) {
+  return async (value) => {
+    return fn(await value);
+  };
+}
+
+var result = 1
+  |> (async (x) => await x + 1)
+  |> then((x) => x + 1);
+
+result.then(val => {
+  assert.equal(val, 3);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/input.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/input.js
new file mode 100644
index 0000000000..648a737a53
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/input.js
@@ -0,0 +1,13 @@
+function then(fn) {
+  return async (value) => {
+    return fn(await value);
+  };
+}
+
+var result = 1
+  |> (async (x) => await x + 1)
+  |> then((x) => x + 1);
+
+result.then(val => {
+  assert.equal(val, 3);
+});
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/options.json b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/options.json
new file mode 100644
index 0000000000..2454c2169c
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/options.json
@@ -0,0 +1,3 @@
+{
+  "minNodeVersion": "8.0.0"
+}
diff --git a/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/output.js b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/output.js
new file mode 100644
index 0000000000..4fb6d4b2a8
--- /dev/null
+++ b/packages/babel-plugin-proposal-pipeline-operator/test/fixtures/pipeline-operator/async-arrow/output.js
@@ -0,0 +1,12 @@
+var _ref, _;
+
+function then(fn) {
+  return async value => {
+    return fn((await value));
+  };
+}
+
+var result = (_ref = (_ = 1, (async x => (await x) + 1)(_)), then(x => x + 1)(_ref));
+result.then(val => {
+  assert.equal(val, 3);
+});