Adds regression tests for issue 2056 (#2124)

Summary:
Release notes: none

It turns out that the tests in https://github.com/facebook/prepack/issues/2056 now pass on master, so this adds regression tests for them. Fixes #2056.
Closes https://github.com/facebook/prepack/pull/2124

Differential Revision: D8432504

Pulled By: trueadm

fbshipit-source-id: fce78b4ecfc9cee55cf70868557a3eacac635867

scripts/__snapshots__/test-react.js.snap

@@ -2139,6 +2139,23 @@ ReactStatistics {
 }
 `;
 
+exports[`Test React with JSX input, JSX output Functional component folding Handle mapped arrays from Array.from 1`] = `
+ReactStatistics {
+  "componentsEvaluated": 1,
+  "evaluatedRootNodes": Array [
+    Object {
+      "children": Array [],
+      "message": "",
+      "name": "App",
+      "status": "ROOT",
+    },
+  ],
+  "inlinedComponents": 0,
+  "optimizedNestedClosures": 1,
+  "optimizedTrees": 1,
+}
+`;
+
 exports[`Test React with JSX input, JSX output Functional component folding Havocing of ReactElements should not result in property assignments 1`] = `
 ReactStatistics {
   "componentsEvaluated": 1,
@@ -7072,6 +7089,23 @@ ReactStatistics {
 }
 `;
 
+exports[`Test React with JSX input, create-element output Functional component folding Handle mapped arrays from Array.from 1`] = `
+ReactStatistics {
+  "componentsEvaluated": 1,
+  "evaluatedRootNodes": Array [
+    Object {
+      "children": Array [],
+      "message": "",
+      "name": "App",
+      "status": "ROOT",
+    },
+  ],
+  "inlinedComponents": 0,
+  "optimizedNestedClosures": 1,
+  "optimizedTrees": 1,
+}
+`;
+
 exports[`Test React with JSX input, create-element output Functional component folding Havocing of ReactElements should not result in property assignments 1`] = `
 ReactStatistics {
   "componentsEvaluated": 1,
@@ -12005,6 +12039,23 @@ ReactStatistics {
 }
 `;
 
+exports[`Test React with create-element input, JSX output Functional component folding Handle mapped arrays from Array.from 1`] = `
+ReactStatistics {
+  "componentsEvaluated": 1,
+  "evaluatedRootNodes": Array [
+    Object {
+      "children": Array [],
+      "message": "",
+      "name": "App",
+      "status": "ROOT",
+    },
+  ],
+  "inlinedComponents": 0,
+  "optimizedNestedClosures": 1,
+  "optimizedTrees": 1,
+}
+`;
+
 exports[`Test React with create-element input, JSX output Functional component folding Havocing of ReactElements should not result in property assignments 1`] = `
 ReactStatistics {
   "componentsEvaluated": 1,
@@ -16953,6 +17004,23 @@ ReactStatistics {
 }
 `;
 
+exports[`Test React with create-element input, create-element output Functional component folding Handle mapped arrays from Array.from 1`] = `
+ReactStatistics {
+  "componentsEvaluated": 1,
+  "evaluatedRootNodes": Array [
+    Object {
+      "children": Array [],
+      "message": "",
+      "name": "App",
+      "status": "ROOT",
+    },
+  ],
+  "inlinedComponents": 0,
+  "optimizedNestedClosures": 1,
+  "optimizedTrees": 1,
+}
+`;
+
 exports[`Test React with create-element input, create-element output Functional component folding Havocing of ReactElements should not result in property assignments 1`] = `
 ReactStatistics {
   "componentsEvaluated": 1,

scripts/test-react.js

@@ -421,6 +421,10 @@ function runTestSuite(outputJsx, shouldTranspileSource) {
         await runTest(directory, "array-map2.js");
       });
 
+      it("Handle mapped arrays from Array.from", async () => {
+        await runTest(directory, "array-from.js");
+      });
+
       it("Simple fragments", async () => {
         await runTest(directory, "simple-fragments.js");
       });

test/react/functional-components/array-from.js

@@ -0,0 +1,35 @@
+var React = require('react');
+// the JSX transform converts to React, so we need to add it back in
+this['React'] = React;
+
+function App(props) {
+  var _ref8;
+  var value = (_ref8 = props.feedback) != null
+    ? (_ref8 = _ref8.display_comments) != null
+      ? _ref8.ordering_mode
+      : _ref8
+    : _ref8;
+
+  var items = props.items;
+  var collection = Array.from(items).map(function() {
+    return <span>{value}</span>
+  });
+
+  return <div>{collection}</div>
+}
+
+App.getTrials = function(renderer, Root) {
+  let items = [
+    { title: "Hello world 1", id: 0 },
+    { title: "Hello world 2", id: 1 },
+    { title: "Hello world 3", id: 2 },
+  ];
+  renderer.update(<Root  items={items} feedback={{display_comments: { ordering_mode: 10 }}} />);
+  return [['simple render array map', renderer.toJSON()]];
+};
+
+if (this.__optimizeReactComponentTree) {
+  __optimizeReactComponentTree(App);
+}
+
+module.exports = App;

test/serializer/optimized-functions/RegressionTestForIssue2056.js

@@ -0,0 +1,19 @@
+function fn(arg) {
+  var value = arg.x !== null ? arg.x : 0;
+
+  function fn2() {
+    return value;
+  }
+  global.__optimize && __optimize(fn2);
+
+  return Array.from(arg.arr).map(fn2);
+}
+
+global.__optimize && __optimize(fn);
+
+global.inspect = function() {
+  return JSON.stringify([
+    fn({arr: [1, 2, 3], x: 1}),
+    fn({arr: [1, 2, 3], x: null}),
+  ])
+};