From 5e00c96368fdad8dc8d5fd62598098515bb3669a Mon Sep 17 00:00:00 2001
From: Logan Smyth <loganfsmyth@gmail.com>
Date: Tue, 22 May 2018 14:37:06 -0700
Subject: [PATCH] Handle Infinity, -Infinity, NaN, and -0 in t.valueToNode().
 (#8005)
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| Q                        | A <!--(Can use an emoji 👍) -->
| ------------------------ | ---
| Fixed Issues?            | Fixes #8001
| Patch: Bug Fix?          | Y
| Major: Breaking Change?  | Not unless things were relying on a very specific AST structure as output
| Minor: New Feature?      |
| Tests Added + Pass?      | Yes
| Documentation PR         | <!-- If so, add `[skip ci]` to your commit message to skip CI -->
| Any Dependency Changes?  |
| License                  | MIT

The filed bug was for `-0`, but I also realize that `numericLiteral` also shouldn't be getting `-Infinity`/`Infinity` or `NaN` since those just get stringified with the JS-standard stringification logic which means we get a reference to `NaN` or `Infinity` identifiers, which could have been shadowed in a local scope and thus not be the right value. I've avoided that by generating `NaN` as `0/0` and the infinity values as `1/0` and `-1/0`.
---
 .../babel-types/src/converters/valueToNode.js | 24 +++++++++++++++++-
 packages/babel-types/test/converters.js       | 25 +++++++++++++++++--
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/packages/babel-types/src/converters/valueToNode.js b/packages/babel-types/src/converters/valueToNode.js
index 85aca82e0a..a4f195765c 100644
--- a/packages/babel-types/src/converters/valueToNode.js
+++ b/packages/babel-types/src/converters/valueToNode.js
@@ -12,6 +12,8 @@ import {
   arrayExpression,
   objectProperty,
   objectExpression,
+  unaryExpression,
+  binaryExpression,
 } from "../builders/generated";
 
 export default function valueToNode(value: any): Object {
@@ -37,7 +39,27 @@ export default function valueToNode(value: any): Object {
 
   // numbers
   if (typeof value === "number") {
-    return numericLiteral(value);
+    let result;
+    if (Number.isFinite(value)) {
+      result = numericLiteral(Math.abs(value));
+    } else {
+      let numerator;
+      if (Number.isNaN(value)) {
+        // NaN
+        numerator = numericLiteral(0);
+      } else {
+        // Infinity / -Infinity
+        numerator = numericLiteral(1);
+      }
+
+      result = binaryExpression("/", numerator, numericLiteral(0));
+    }
+
+    if (value < 0 || Object.is(value, -0)) {
+      result = unaryExpression("-", result);
+    }
+
+    return result;
   }
 
   // regexes
diff --git a/packages/babel-types/test/converters.js b/packages/babel-types/test/converters.js
index f3966c7f3a..29c9abb378 100644
--- a/packages/babel-types/test/converters.js
+++ b/packages/babel-types/test/converters.js
@@ -19,8 +19,29 @@ describe("converters", function() {
   describe("valueToNode", function() {
     it("number", function() {
       expect(t.valueToNode(Math.PI)).toEqual(t.numericLiteral(Math.PI));
-      expect(t.valueToNode(-Infinity)).toEqual(t.numericLiteral(-Infinity));
-      expect(t.valueToNode(NaN)).toEqual(t.numericLiteral(NaN));
+      expect(t.valueToNode(-Math.PI)).toEqual(
+        t.unaryExpression("-", t.numericLiteral(Math.PI)),
+      );
+      expect(t.valueToNode(0)).toEqual(t.numericLiteral(0));
+      expect(t.valueToNode(-0)).toEqual(
+        t.unaryExpression("-", t.numericLiteral(0)),
+      );
+      expect(t.valueToNode(NaN)).toEqual(
+        t.binaryExpression("/", t.numericLiteral(0), t.numericLiteral(0)),
+      );
+      expect(t.valueToNode(-NaN)).toEqual(
+        t.binaryExpression("/", t.numericLiteral(0), t.numericLiteral(0)),
+      );
+
+      expect(t.valueToNode(Infinity)).toEqual(
+        t.binaryExpression("/", t.numericLiteral(1), t.numericLiteral(0)),
+      );
+      expect(t.valueToNode(-Infinity)).toEqual(
+        t.unaryExpression(
+          "-",
+          t.binaryExpression("/", t.numericLiteral(1), t.numericLiteral(0)),
+        ),
+      );
     });
     it("string", function() {
       expect(t.valueToNode('This is a "string"')).toEqual(