[New] add support for arrays with additional object keys

(node’s util.format does this as well)

Author: ljharb

index.js

@@ -71,24 +71,10 @@ module.exports = function inspect_ (obj, opts, depth, seen) {
     }
     if (isArray(obj)) {
         if (obj.length === 0) return '[]';
-        var xs = Array(obj.length);
-        for (var i = 0; i < obj.length; i++) {
-            xs[i] = has(obj, i) ? inspect(obj[i], obj) : '';
-        }
-        return '[ ' + xs.join(', ') + ' ]';
+        return '[ ' + arrObjKeys(obj, inspect).join(', ') + ' ]';
     }
     if (isError(obj)) {
-        var parts = [];
-        for (var key in obj) {
-            if (!has(obj, key)) continue;
-            
-            if (/[^\w$]/.test(key)) {
-                parts.push(inspect(key) + ': ' + inspect(obj[key]));
-            }
-            else {
-                parts.push(key + ': ' + inspect(obj[key]));
-            }
-        }
+        var parts = arrObjKeys(obj, inspect);
         if (parts.length === 0) return '[' + String(obj) + ']';
         return '{ [' + String(obj) + '] ' + parts.join(', ') + ' }';
     }
@@ -119,30 +105,13 @@ module.exports = function inspect_ (obj, opts, depth, seen) {
         return markBoxed(inspect(String(obj)));
     }
     if (!isDate(obj) && !isRegExp(obj)) {
-        var xs = [];
-        var keys = objectKeys(obj);
-        keys.sort();
-        for (var i = 0; i < keys.length; i++) {
-            var key = keys[i];
-            if (/[^\w$]/.test(key)) {
-                xs.push(inspect(key) + ': ' + inspect(obj[key], obj));
-            }
-            else xs.push(key + ': ' + inspect(obj[key], obj));
-        }
+        var xs = arrObjKeys(obj, inspect);
         if (xs.length === 0) return '{}';
         return '{ ' + xs.join(', ') + ' }';
     }
     return String(obj);
 };
 
-function objectKeys(obj) {
-    var keys = [];
-    for (var key in obj) {
-        if (has(obj, key)) keys.push(key);
-    }
-    return keys;
-}
-
 function quote (s) {
     return String(s).replace(/"/g, '&quot;');
 }
@@ -227,6 +196,27 @@ function markBoxed (str) {
     return 'Object(' + str + ')';
 }
 
-function collectionOf(type, size, entries) {
+function collectionOf (type, size, entries) {
     return type + ' (' + size + ') {' + entries.join(', ') + '}';
 }
+
+function arrObjKeys (obj, inspect) {
+    var isArr = isArray(obj);
+    var xs = [];
+    if (isArr) {
+        xs.length = obj.length;
+        for (var i = 0; i < obj.length; i++) {
+            xs[i] = has(obj, i) ? inspect(obj[i], obj) : '';
+        }
+    }
+    for (var key in obj) {
+        if (!has(obj, key)) continue;
+        if (isArr && String(Number(key)) === key && key < obj.length) continue;
+        if (/[^\w$]/.test(key)) {
+            xs.push(inspect(key, obj) + ': ' + inspect(obj[key], obj));
+        } else {
+            xs.push(key + ': ' + inspect(obj[key], obj));
+        }
+    }
+    return xs;
+}

test/values.js

@@ -7,6 +7,16 @@ test('values', function (t) {
     t.equal(inspect(obj), '[ {}, [], { \'a-b\': 5 } ]');
 });
 
+test('arrays with properties', function (t) {
+   t.plan(1);
+   var arr = [3];
+   arr.foo = 'bar';
+   var obj = [1, 2, arr];
+   obj.baz = 'quux';
+   obj.index = -1;
+   t.equal(inspect(obj), '[ 1, 2, [ 3, foo: \'bar\' ], baz: \'quux\', index: -1 ]');
+});
+
 test('has', function (t) {
     t.plan(1);
     var has = Object.prototype.hasOwnProperty;