only deduplicate non-primitives

Author: Rich-Harris

src/uneval.js

@@ -30,14 +30,14 @@ export function uneval(value) {
 			throw new DevalueError(`Cannot stringify a function`, keys);
 		}
 
-		if (counts.has(thing)) {
-			counts.set(thing, counts.get(thing) + 1);
-			return;
-		}
+		if (!is_primitive(thing)) {
+			if (counts.has(thing)) {
+				counts.set(thing, counts.get(thing) + 1);
+				return;
+			}
 
-		counts.set(thing, 1);
+			counts.set(thing, 1);
 
-		if (!is_primitive(thing)) {
 			const type = get_type(thing);
 
 			switch (type) {

test/test.js

@@ -299,9 +299,25 @@ const fixtures = {
 		{
 			name: 'String (repetition)',
 			value: ['a string', 'a string'],
-			js: '(function(a){return [a,a]}("a string"))',
+			js: '["a string","a string"]',
 			json: '[[1,1],"a string"]'
-		}
+		},
+
+		{
+			name: 'null (repetition)',
+			value: [null, null],
+			js: '[null,null]',
+			json: '[[1,1],null]'
+		},
+
+		((object) => {
+			return {
+				name: 'Object (repetition)',
+				value: [object, object],
+				js: '(function(a){return [a,a]}({}))',
+				json: '[[1,1],{}]'
+			};
+		})({})
 	],
 
 	XSS: [