From 585007396f5f94f8a40ccc84b20edbdfd7a80dd1 Mon Sep 17 00:00:00 2001
From: Jack Cross <jackjocross@gmail.com>
Date: Thu, 5 Oct 2017 09:42:59 -0400
Subject: [PATCH] Added step over functionality for yield (#4232) (#4276)

* Added step over functionality for yield (#4232)

* Consistent parser steps naming and generators fixture
---
 src/workers/parser/steps.js                   | 21 +++---
 .../parser/tests/fixtures/generators.js       |  4 ++
 src/workers/parser/tests/steps.spec.js        | 65 ++++++++++++-------
 src/workers/parser/utils/helpers.js           |  8 +++
 4 files changed, 63 insertions(+), 35 deletions(-)
 create mode 100644 src/workers/parser/tests/fixtures/generators.js

diff --git a/src/workers/parser/steps.js b/src/workers/parser/steps.js
index 29af7f4aed..ec4ab43c47 100644
--- a/src/workers/parser/steps.js
+++ b/src/workers/parser/steps.js
@@ -1,36 +1,33 @@
 import { Source } from "../../../flow-typed/debugger-html";
 import { AstPosition } from "./types";
 import { getClosestPath } from "./utils/closest";
-import { isAwaitExpression } from "./utils/helpers";
+import { isAwaitExpression, isYieldExpression } from "./utils/helpers";
 import type { NodePath } from "babel-traverse";
 
 export function getNextStep(source: Source, pausedPosition: AstPosition) {
-  const awaitExpression = getAwaitExpression(source, pausedPosition);
-  if (!awaitExpression) {
+  const currentExpression = getSteppableExpression(source, pausedPosition);
+  if (!currentExpression) {
     return null;
   }
-  const awaitStatement = awaitExpression.getStatementParent();
-  return getLocationAfterAwaitExpression(awaitStatement, pausedPosition);
+  const currentStatement = currentExpression.getStatementParent();
+  return _getNextStep(currentStatement, pausedPosition);
 }
 
-function getAwaitExpression(source: Source, pausedPosition: AstPosition) {
+function getSteppableExpression(source: Source, pausedPosition: AstPosition) {
   const closestPath = getClosestPath(source, pausedPosition);
 
   if (!closestPath) {
     return null;
   }
 
-  if (isAwaitExpression(closestPath)) {
+  if (isAwaitExpression(closestPath) || isYieldExpression(closestPath)) {
     return closestPath;
   }
 
-  return closestPath.find(p => p.isAwaitExpression());
+  return closestPath.find(p => p.isAwaitExpression() || p.isYieldExpression());
 }
 
-function getLocationAfterAwaitExpression(
-  statement: NodePath,
-  position: AstPosition
-) {
+function _getNextStep(statement: NodePath, position: AstPosition) {
   const nextStatement = statement.getSibling(statement.key + 1);
   if (nextStatement.node) {
     return {
diff --git a/src/workers/parser/tests/fixtures/generators.js b/src/workers/parser/tests/fixtures/generators.js
new file mode 100644
index 0000000000..7c71838827
--- /dev/null
+++ b/src/workers/parser/tests/fixtures/generators.js
@@ -0,0 +1,4 @@
+function* foo() {
+  yield 1;
+  yield 2;
+}
diff --git a/src/workers/parser/tests/steps.spec.js b/src/workers/parser/tests/steps.spec.js
index f00c523a7a..737a657086 100644
--- a/src/workers/parser/tests/steps.spec.js
+++ b/src/workers/parser/tests/steps.spec.js
@@ -2,34 +2,53 @@ import { getNextStep } from "../steps";
 import { getSource } from "./helpers";
 
 describe("getNextStep", () => {
-  it("first await call", () => {
-    const source = getSource("async");
-    const pausePosition = { line: 8, column: 2, sourceId: "async" };
-    expect(getNextStep(source, pausePosition)).toEqual({
-      ...pausePosition,
-      line: 9
+  describe("await", () => {
+    it("first await call", () => {
+      const source = getSource("async");
+      const pausePosition = { line: 8, column: 2, sourceId: "async" };
+      expect(getNextStep(source, pausePosition)).toEqual({
+        ...pausePosition,
+        line: 9
+      });
     });
-  });
 
-  it("first await call expression", () => {
-    const source = getSource("async");
-    const pausePosition = { line: 8, column: 9, sourceId: "async" };
-    expect(getNextStep(source, pausePosition)).toEqual({
-      ...pausePosition,
-      line: 9,
-      column: 2
+    it("first await call expression", () => {
+      const source = getSource("async");
+      const pausePosition = { line: 8, column: 9, sourceId: "async" };
+      expect(getNextStep(source, pausePosition)).toEqual({
+        ...pausePosition,
+        line: 9,
+        column: 2
+      });
+    });
+
+    it("second await call", () => {
+      const source = getSource("async");
+      const pausePosition = { line: 9, column: 2, sourceId: "async" };
+      expect(getNextStep(source, pausePosition)).toEqual(null);
     });
-  });
 
-  it("second await call", () => {
-    const source = getSource("async");
-    const pausePosition = { line: 9, column: 2, sourceId: "async" };
-    expect(getNextStep(source, pausePosition)).toEqual(null);
+    it("second call expression", () => {
+      const source = getSource("async");
+      const pausePosition = { line: 9, column: 9, sourceId: "async" };
+      expect(getNextStep(source, pausePosition)).toEqual(null);
+    });
   });
 
-  it("second call expression", () => {
-    const source = getSource("async");
-    const pausePosition = { line: 9, column: 9, sourceId: "async" };
-    expect(getNextStep(source, pausePosition)).toEqual(null);
+  describe("yield", () => {
+    it("first yield call", () => {
+      const source = getSource("generators");
+      const pausePosition = { line: 2, column: 2, sourceId: "generators" };
+      expect(getNextStep(source, pausePosition)).toEqual({
+        ...pausePosition,
+        line: 3
+      });
+    });
+
+    it("second yield call", () => {
+      const source = getSource("generators");
+      const pausePosition = { line: 3, column: 2, sourceId: "generators" };
+      expect(getNextStep(source, pausePosition)).toEqual(null);
+    });
   });
 });
diff --git a/src/workers/parser/utils/helpers.js b/src/workers/parser/utils/helpers.js
index 03e89826bc..6e4f860837 100644
--- a/src/workers/parser/utils/helpers.js
+++ b/src/workers/parser/utils/helpers.js
@@ -24,6 +24,14 @@ export function isAwaitExpression(path: NodePath) {
   );
 }
 
+export function isYieldExpression(path: NodePath) {
+  return (
+    t.isYieldExpression(path) ||
+    t.isYieldExpression(path.container.init) ||
+    t.isYieldExpression(path.parentPath)
+  );
+}
+
 export function isVariable(path: NodePath) {
   return (
     t.isVariableDeclaration(path) ||