Add "allowArrayLike" opt to destructuring and spread transforms (#11265)

packages/babel-plugin-transform-spread/src/index.js

@@ -4,13 +4,13 @@ import { types as t } from "@babel/core";
 export default declare((api, options) => {
   api.assertVersion(7);
 
-  const { loose } = options;
+  const { loose, allowArrayLike } = options;
 
   function getSpreadLiteral(spread, scope) {
     if (loose && !t.isIdentifier(spread.argument, { name: "arguments" })) {
       return spread.argument;
     } else {
-      return scope.toArray(spread.argument, true);
+      return scope.toArray(spread.argument, true, allowArrayLike);
     }
   }
 

packages/babel-plugin-transform-spread/test/fixtures/allowArrayLike/holes/exec.js

@@ -0,0 +1,6 @@
+var p2 = { 0: "a", 2: "c", length: 3 };
+
+var arr = [...p2, "d"];
+
+expect(arr).toEqual(["a", undefined, "c", "d"]);
+expect(1 in arr).toBe(true); // Not holey

packages/babel-plugin-transform-spread/test/fixtures/allowArrayLike/holes/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    ["transform-spread", { "allowArrayLike": true }]
+  ]
+}

packages/babel-plugin-transform-spread/test/fixtures/allowArrayLike/length-cropped/exec.js

@@ -0,0 +1,5 @@
+var p2 = { 0: "b", 1: "c", 2: "d", length: 2 };
+
+var arr = ["a", ...p2, "e"];
+
+expect(arr).toEqual(["a", "b", "c", "e"]);

packages/babel-plugin-transform-spread/test/fixtures/allowArrayLike/length-cropped/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    ["transform-spread", { "allowArrayLike": true }]
+  ]
+}

packages/babel-plugin-transform-spread/test/fixtures/allowArrayLike/simple/exec.js

@@ -0,0 +1,5 @@
+var p2 = { 0: "b", 1: "c", 2: "d", length: 3 };
+
+var arr = ["a", ...p2, "e"];
+
+expect(arr).toEqual(["a", "b", "c", "d", "e"]);

packages/babel-plugin-transform-spread/test/fixtures/allowArrayLike/simple/input.js

@@ -0,0 +1 @@
+var arr = ["a", ...p2, "e"];

packages/babel-plugin-transform-spread/test/fixtures/allowArrayLike/simple/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    ["transform-spread", { "allowArrayLike": true }]
+  ]
+}

packages/babel-plugin-transform-spread/test/fixtures/allowArrayLike/simple/output.js

@@ -0,0 +1 @@
+var arr = ["a"].concat(babelHelpers.maybeArrayLike(babelHelpers.toConsumableArray, p2), ["e"]);