Don't polyfill if evaluation is not confident (#10397)

babel · Sep 5, 2019 · 5c859b1 · 5c859b1
1 parent 2e7bea4
commit 5c859b1
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Showing 4 changed files with 33 additions and 1 deletion.
diff --git a/packages/babel-preset-env/src/polyfills/corejs2/usage-plugin.js b/packages/babel-preset-env/src/polyfills/corejs2/usage-plugin.js
@@ -107,7 +107,7 @@ export default function(
         if (isNamespaced(path.get("object"))) return;
 
         let evaluatedPropType = object.name;
-        let propertyName = property.name;
+        let propertyName = "";
         let instanceType = "";
 
         if (node.computed) {
@@ -119,6 +119,8 @@ export default function(
               propertyName = result.value;
             }
           }
+        } else {
+          propertyName = property.name;
         }
 
         if (path.scope.getBindingIdentifier(object.name)) {

diff --git a/packages/babel-preset-env/test/fixtures/corejs2/usage-evaluated-not-confident/input.mjs b/packages/babel-preset-env/test/fixtures/corejs2/usage-evaluated-not-confident/input.mjs
@@ -0,0 +1,5 @@
+Object['values'](); // include
+[]['map'](); // include
+
+Object[keys](); // don't include
+[][filter](); // don't include
diff --git a/packages/babel-preset-env/test/fixtures/corejs2/usage-evaluated-not-confident/options.json b/packages/babel-preset-env/test/fixtures/corejs2/usage-evaluated-not-confident/options.json
@@ -0,0 +1,12 @@
+{
+  "presets": [
+    [
+      "../../../../lib",
+      {
+        "useBuiltIns": "usage",
+        "corejs": 2,
+        "modules": false
+      }
+    ]
+  ]
+}
diff --git a/packages/babel-preset-env/test/fixtures/corejs2/usage-evaluated-not-confident/output.mjs b/packages/babel-preset-env/test/fixtures/corejs2/usage-evaluated-not-confident/output.mjs
@@ -0,0 +1,13 @@
+import "core-js/modules/es6.array.map";
+import "core-js/modules/web.dom.iterable";
+import "core-js/modules/es6.array.iterator";
+import "core-js/modules/es6.object.to-string";
+import "core-js/modules/es7.object.values";
+Object['values'](); // include
+
+[]['map'](); // include
+
+Object[keys](); // don't include
+
+[][filter](); // don't include
+