BaseNode.clone()

Author: Pike

fluent-syntax/src/ast.js

@@ -51,6 +51,23 @@ class BaseNode {
     }
     return true;
   }
+
+  clone() {
+    function visit(value) {
+      if (value instanceof BaseNode) {
+        return value.clone();
+      }
+      if (Array.isArray(value)) {
+        return value.map(visit);
+      }
+      return value;
+    }
+    const clone = Object.create(this);
+    for (const prop of Object.keys(this)) {
+      clone[prop] = visit(this[prop]);
+    }
+    return clone;
+  }
 }
 
 function scalars_equal(thisVal, otherVal, ignoredFields) {

fluent-syntax/test/ast_test.js

@@ -13,6 +13,8 @@ suite("BaseNode.equals", function() {
     const thisNode = new AST.Identifier("name");
     const otherNode = new AST.Identifier("name");
     assert.strictEqual(thisNode.equals(otherNode), true);
+    assert.strictEqual(thisNode.equals(thisNode.clone()), true);
+    assert.notStrictEqual(thisNode, thisNode.clone());
   });
   test("Node.type", function() {
     const thisNode = new AST.Identifier("name");
@@ -54,6 +56,8 @@ suite("BaseNode.equals", function() {
       assert.strictEqual(thisNode.equals(otherNode, ['span', 'comment']), true);
       assert.strictEqual(thisNode.value.equals(otherNode.value), true);
       assert.strictEqual(thisNode.value.equals(otherNode.value, []), false);
+      assert.strictEqual(thisRes.equals(thisRes.clone(), []), true);
+      assert.notStrictEqual(thisRes, thisRes.clone());
   });
   test("Attributes without order", function() {
       const thisRes = this.parser.parse(ftl`