From ba6bb0fccf21d6b2c6eeb7a6e1036b0071711c2c Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Tue, 10 Sep 2019 20:28:13 +0100
Subject: [PATCH] [Fresh] Hash signatures (#16738)

---
 .../react-refresh/src/ReactFreshBabelPlugin.js  | 17 +++++++++++++++--
 .../src/__tests__/ReactFreshBabelPlugin-test.js |  9 ++++++++-
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/packages/react-refresh/src/ReactFreshBabelPlugin.js b/packages/react-refresh/src/ReactFreshBabelPlugin.js
index ff41422ca812..f1a92e9da8e0 100644
--- a/packages/react-refresh/src/ReactFreshBabelPlugin.js
+++ b/packages/react-refresh/src/ReactFreshBabelPlugin.js
@@ -7,7 +7,7 @@
 
 'use strict';
 
-export default function(babel, opts) {
+export default function(babel, opts = {}) {
   if (typeof babel.getEnv === 'function') {
     // Only available in Babel 7.
     const env = babel.getEnv();
@@ -300,7 +300,20 @@ export default function(babel, opts) {
       }
     });
 
-    const args = [node, t.stringLiteral(key)];
+    let finalKey = key;
+    if (typeof require === 'function' && !opts.emitFullSignatures) {
+      // Prefer to hash when we can (e.g. outside of ASTExplorer).
+      // This makes it deterministically compact, even if there's
+      // e.g. a useState ininitalizer with some code inside.
+      // We also need it for www that has transforms like cx()
+      // that don't understand if something is part of a string.
+      finalKey = require('crypto')
+        .createHash('sha1')
+        .update(key)
+        .digest('base64');
+    }
+
+    const args = [node, t.stringLiteral(finalKey)];
     if (forceReset || customHooksInScope.length > 0) {
       args.push(t.booleanLiteral(forceReset));
     }
diff --git a/packages/react-refresh/src/__tests__/ReactFreshBabelPlugin-test.js b/packages/react-refresh/src/__tests__/ReactFreshBabelPlugin-test.js
index 7544d4eea7a2..ed7bd8cd15c4 100644
--- a/packages/react-refresh/src/__tests__/ReactFreshBabelPlugin-test.js
+++ b/packages/react-refresh/src/__tests__/ReactFreshBabelPlugin-test.js
@@ -19,7 +19,14 @@ function transform(input, options = {}) {
       plugins: [
         '@babel/syntax-jsx',
         '@babel/syntax-dynamic-import',
-        [freshPlugin, {skipEnvCheck: true}],
+        [
+          freshPlugin,
+          {
+            skipEnvCheck: true,
+            // To simplify debugging tests:
+            emitFullSignatures: true,
+          },
+        ],
         ...(options.plugins || []),
       ],
     }).code,