[Breaking] boxed primitives are unwrapped for comparisons

Author: ljharb

index.js

@@ -5,6 +5,8 @@ var isRegex = require('is-regex');
 var flags = require('regexp.prototype.flags');
 var isArray = require('isarray');
 var isDate = require('is-date-object');
+var isBoxedPrimitive = require('is-boxed-primitive');
+var toPrimitive = require('es-to-primitive/es2015'); // TODO: replace this with ES2020 once updated
 
 var getTime = Date.prototype.getTime;
 var gPO = Object.getPrototypeOf;
@@ -18,6 +20,12 @@ function deepEqual(actual, expected, options) {
     return true;
   }
 
+  var actualBoxed = isBoxedPrimitive(actual);
+  var expectedBoxed = isBoxedPrimitive(expected);
+  if (actualBoxed || expectedBoxed) {
+    return deepEqual(toPrimitive(actual), toPrimitive(expected), opts);
+  }
+
   // 7.3. Other pairs that do not both pass typeof value == 'object', equivalence is determined by ==.
   if (!actual || !expected || (typeof actual !== 'object' && typeof expected !== 'object')) {
     return opts.strict ? is(actual, expected) : actual == expected;
@@ -53,8 +61,9 @@ function isBuffer(x) {
 }
 
 function objEquiv(a, b, opts) {
-  /* eslint max-statements: [2, 70] */
+  /* eslint max-statements: [2, 70], max-lines-per-function: [2, 80] */
   var i, key;
+
   if (typeof a !== typeof b) { return false; }
   if (isUndefinedOrNull(a) || isUndefinedOrNull(b)) { return false; }
 
@@ -121,6 +130,7 @@ function objEquiv(a, b, opts) {
   for (i = ka.length - 1; i >= 0; i--) {
     if (ka[i] != kb[i]) { return false; }
   }
+
   // equivalent values for every corresponding key, and ~~~possibly expensive deep test
   for (i = ka.length - 1; i >= 0; i--) {
     key = ka[i];

package.json

@@ -15,7 +15,9 @@
     "test": "npm run tests-only"
   },
   "dependencies": {
+    "es-to-primitive": "^1.2.0",
     "is-arguments": "^1.0.4",
+    "is-boxed-primitive": "^1.0.0",
     "is-date-object": "^1.0.1",
     "is-regex": "^1.0.4",
     "isarray": "^2.0.5",

test/cmp.js

@@ -419,3 +419,27 @@ test('toStringTag', { skip: !hasSymbols || !Symbol.toStringTag }, function (t) {
 
   t.end();
 });
+
+test('boxed primitives', function (t) {
+  t.deepEqualTest(Object(false), false, 'boxed and primitive `false`', true, true);
+  t.deepEqualTest(Object(true), true, 'boxed and primitive `true`', true, true);
+  t.deepEqualTest(Object(3), 3, 'boxed and primitive `3`', true, true);
+  t.deepEqualTest(Object(NaN), NaN, 'boxed and primitive `NaN`', false, true);
+  t.deepEqualTest(Object(''), '', 'boxed and primitive `""`', true, true);
+  t.deepEqualTest(Object('str'), 'str', 'boxed and primitive `"str"`', true, true);
+
+  t.test('symbol', { skip: !hasSymbols }, function (st) {
+    var s = Symbol('');
+    st.deepEqualTest(Object(s), s, 'boxed and primitive `Symbol()`', true, true);
+    st.end();
+  });
+
+  /* globals BigInt: false */
+  t.test('bigint', { skip: typeof BigInt !== 'function' }, function (st) {
+    var hhgtg = BigInt(42);
+    st.deepEqualTest(Object(hhgtg), hhgtg, 'boxed and primitive `BigInt(42)`', true, true);
+    st.end();
+  });
+
+  t.end();
+});