Fix a false-positive for circular object

Fixes #2

index.js

@@ -1,24 +1,19 @@
 const makeCircularReplacer = () => {
- const seen = new WeakSet();
+ const seen = new WeakMap();
 
  return (key, value) => {
  if (value !== null && typeof value === 'object') {
- if (seen.has(value)) {
+ if (seen.has(value) && seen.get(value) !== key) {
  return '[Circular]';
  }
 
- seen.add(value);
+ seen.set(value, key);
  }
 
  return value;
  };
 };
 
 export default function safeStringify(object, {indentation} = {}) {
- // Without this, the replacer would replace duplicate objects in a top-level array.
- if (Array.isArray(object)) {
- object = object.map(element => JSON.parse(JSON.stringify(element, makeCircularReplacer())));
- }
-
  return JSON.stringify(object, makeCircularReplacer(), indentation);
 }

readme.md

@@ -55,4 +55,4 @@ Set it to `'\t'` for tab indentation or the number of spaces you want.
 
 ### Why another safe stringify package?
 
-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.
+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.

test.js

@@ -1,6 +1,10 @@
 import test from 'ava';
 import safeStringify from './index.js';
 
+const options = {
+ indentation: '\t',
+};
+
 test('main', t => {
  const fixture = {
  a: true,
@@ -9,7 +13,7 @@ test('main', t => {
  },
  };
 
- t.is(safeStringify(fixture, {indentation: '\t'}), JSON.stringify(fixture, undefined, '\t'));
+ t.is(safeStringify(fixture, options), JSON.stringify(fixture, undefined, '\t'));
 });
 
 test('circular object', t => {
@@ -25,15 +29,33 @@ test('circular object', t => {
  e: fixture.c,
  };
 
- t.snapshot(safeStringify(fixture));
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('circular array', t => {
+ const fixture = [1];
+
+ fixture.push(fixture, fixture);
+
+ t.snapshot(safeStringify(fixture, options));
+});
+
+test('multiple circular objects in array', t => {
+ const fixture = {
+ a: true,
+ };
+
+ fixture.b = fixture;
+
+ t.snapshot(safeStringify([fixture, fixture], options));
 });
 
-test('multiple circular objects', t => {
+test('multiple circular objects in object', t => {
  const fixture = {
  a: true,
  };
 
  fixture.b = fixture;
 
- t.snapshot(safeStringify([fixture, fixture]));
+ t.snapshot(safeStringify({x: fixture, y: fixture}, options));
 });

test.js.md

@@ -8,10 +8,48 @@ Generated by [AVA](https://avajs.dev).
 
 > Snapshot 1
 
- '{"a":true,"b":"[Circular]","c":["[Circular]","[Circular]"],"d":{"e":"[Circular]"}}'
+ `{␊
+  "a": true,␊
+  "b": "[Circular]",␊
+  "c": [␊
+  "[Circular]",␊
+  "[Circular]"␊
+  ],␊
+  "d": {␊
+  "e": "[Circular]"␊
+  }␊
+ }`
+
+## circular array
 
-## multiple circular objects
+> Snapshot 1
+
+ `[␊
+  1,␊
+  "[Circular]",␊
+  "[Circular]"␊
+ ]`
+
+## multiple circular objects in array
+
+> Snapshot 1
+
+ `[␊
+  {␊
+  "a": true,␊
+  "b": "[Circular]"␊
+  },␊
+  "[Circular]"␊
+ ]`
+
+## multiple circular objects in object
 
 > Snapshot 1
 
- '[{"a":true,"b":"[Circular]"},{"a":true,"b":"[Circular]"}]'
+ `{␊
+  "x": {␊
+  "a": true,␊
+  "b": "[Circular]"␊
+  },␊
+  "y": "[Circular]"␊
+ }`