feat: handles inspection of objects with circular references (#47)

Fix #44
chaijs · Jun 24, 2021 · 1664d70 · 1664d70
1 parent 5e76830
commit 1664d70
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diff --git a/lib/object.js b/lib/object.js
@@ -7,6 +7,11 @@ export default function inspectObject(object, options) {
     return '{}'
   }
   options.truncate -= 4
+  options.seen = options.seen || []
+  if (options.seen.indexOf(object) >= 0) {
+    return '[Circular]'
+  }
+  options.seen.push(object)
   const propertyContents = inspectList(
     properties.map(key => [key, object[key]]),
     options,
@@ -17,6 +22,7 @@ export default function inspectObject(object, options) {
     options,
     inspectProperty
   )
+  options.seen.pop()
   let sep = ''
   if (propertyContents && symbolContents) {
     sep = ', '

diff --git a/test/objects.js b/test/objects.js
@@ -10,6 +10,14 @@ for (const [suite, inspect] of Object.entries({
       expect(inspect({})).to.equal('{}')
     })
 
+    if (suite === 'objects') {
+      it('detects circular references', () => {
+        const main = {}
+        main.a = main
+        expect(inspect(main)).to.equal('{ a: [Circular] }')
+      })
+    }
+
     describe('truncate', () => {
       it('returns the full representation when truncate is over string length', () => {
         expect(inspect({ a: 1, b: 2, c: 3 }, { truncate: 20 })).to.equal('{ a: 1, b: 2, c: 3 }')