Fix circular false-positive

Fixes #2

index.js

@@ -1,19 +1,28 @@
-const makeCircularReplacer = () => {
- const seen = new WeakMap();
-
- return (key, value) => {
+function safeStringifyReplacer(seen) {
+ return function (key, value) {
  if (value !== null && typeof value === 'object') {
- if (seen.has(value) && seen.get(value) !== key) {
+ if (seen.has(value)) {
  return '[Circular]';
  }
 
- seen.set(value, key);
+ seen.add(value);
+
+ const newValue = Array.isArray(value) ? [] : {};
+
+ for (const [key2, value2] of Object.entries(value)) {
+ newValue[key2] = safeStringifyReplacer(seen)(key2, value2);
+ }
+
+ seen.delete(value);
+
+ return newValue;
  }
 
  return value;
  };
-};
+}
 
 export default function safeStringify(object, {indentation} = {}) {
- return JSON.stringify(object, makeCircularReplacer(), indentation);
+ const seen = new WeakSet();
+ return JSON.stringify(object, safeStringifyReplacer(seen), indentation);
 }

package.json

@@ -34,8 +34,8 @@
  "object"
  ],
  "devDependencies": {
- "ava": "^4.1.0",
- "tsd": "^0.20.0",
- "xo": "^0.48.0"
+ "ava": "^5.2.0",
+ "tsd": "^0.28.0",
+ "xo": "^0.53.1"
  }
 }

readme.md

@@ -35,6 +35,8 @@ Returns a string.
 
 #### value
 
+Type: `unknown`
+
 The value to convert to a JSON string.
 
 #### options
@@ -47,12 +49,10 @@ Type: `'string' | 'number'`
 
 The indentation of the JSON.
 
-By default, the JSON is not indented.
-
-Set it to `'\t'` for tab indentation or the number of spaces you want.
+By default, the JSON is not indented. Set it to `'\t'` for tab indentation or the number of spaces you want.
 
 ## FAQ
 
 ### Why another safe stringify package?
 
-The existing ones either did too much, did it incorrectly, or used inefficient code (not using `WeakMap`). For example, many packages incorrectly replaced all duplicate objects, not just circular references, and did not handle circular arrays.
+The existing ones either did too much, did it incorrectly, or used inefficient code (not using `WeakSet`). For example, many packages incorrectly replaced all duplicate objects, not just circular references, and did not handle circular arrays.

test.js

@@ -32,18 +32,18 @@ test('circular object', t => {
  t.snapshot(safeStringify(fixture, options));
 });
 
-/// test('circular object 2', t => {
-//  const fixture2 = {
-//  c: true,
-//  };
+test('circular object 2', t => {
+ const fixture2 = {
+ c: true,
+ };
 
-//  const fixture = {
-//  a: fixture2,
-//  b: fixture2,
-//  };
+ const fixture = {
+ a: fixture2,
+ b: fixture2,
+ };
 
-//  t.snapshot(safeStringify(fixture, options));
-// });
+ t.snapshot(safeStringify(fixture, options));
+});
 
 test('circular array', t => {
  const fixture = [1];
@@ -72,3 +72,147 @@ test('multiple circular objects in object', t => {
 
  t.snapshot(safeStringify({x: fixture, y: fixture}, options));
 });
+
+test('nested non-circular object', t => {
+ const fixture = {
+ a: {
+ b: {
+ c: {
+ d: 1,
+ },
+ },
+ },
+ };
+
+ t.is(safeStringify(fixture, options), JSON.stringify(fixture, undefined, '\t'));
+});
+
+test('nested circular object', t => {
+ const fixture = {
+ a: {
+ b: {
+ c: {},
+ },
+ },
+ };
+
+ fixture.a.b.c.d = fixture.a;
+
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('complex object with circular and non-circular references', t => {
+ const shared = {x: 1};
+ const circular = {y: 2};
+ circular.self = circular;
+
+ const fixture = {
+ a: shared,
+ b: {
+ c: shared,
+ d: circular,
+ },
+ e: circular,
+ };
+
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('object with circular references at different depths', t => {
+ const fixture = {
+ a: {
+ b: {
+ c: {},
+ },
+ },
+ };
+
+ fixture.a.b.c.d = fixture.a;
+ fixture.a.b.c.e = fixture.a.b;
+
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('object with value as a circular reference', t => {
+ const fixture = {
+ a: 1,
+ b: 2,
+ };
+
+ fixture.self = fixture;
+
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('empty object', t => {
+ const fixture = {};
+
+ t.is(safeStringify(fixture, options), JSON.stringify(fixture, undefined, '\t'));
+});
+
+test('object with null value', t => {
+ const fixture = {
+ a: null,
+ };
+
+ t.is(safeStringify(fixture, options), JSON.stringify(fixture, undefined, '\t'));
+});
+
+test('object with undefined value', t => {
+ const fixture = {
+ a: undefined,
+ };
+
+ t.is(safeStringify(fixture, options), JSON.stringify(fixture, undefined, '\t'));
+});
+
+test('circular object with multiple nested circular references', t => {
+ const fixture = {
+ a: {
+ b: {
+ c: {},
+ },
+ },
+ };
+
+ fixture.a.b.c.d = fixture.a;
+ fixture.a.b.c.e = fixture.a.b;
+ fixture.a.b.c.f = fixture.a.b.c;
+
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('circular array with nested circular arrays', t => {
+ const fixture = [[1, 2, 3]];
+
+ fixture.push(fixture, [fixture, fixture]);
+
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('object with circular reference to parent and grandparent', t => {
+ const fixture = {
+ a: {
+ b: {
+ c: {},
+ },
+ },
+ };
+
+ fixture.a.b.c.parent = fixture.a.b;
+ fixture.a.b.c.grandparent = fixture.a;
+
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('array containing objects with the same circular reference', t => {
+ const circular = {a: 1};
+ circular.self = circular;
+
+ const fixture = [
+ {b: 2, c: circular},
+ {d: 3, e: circular},
+ ];
+
+ t.snapshot(safeStringify(fixture, options));
+});