Expose strict mode functionality

Author: lukechilds

assert.js

@@ -483,6 +483,18 @@ assert.doesNotThrow = function(block, /*optional*/error, /*optional*/message) {
 
 assert.ifError = function(err) { if (err) throw err; };
 
+// Expose a strict only variant of assert
+function strict(value, message) {
+  if (!value) fail(value, true, message, '==', strict);
+}
+assert.strict = Object.assign(strict, assert, {
+  equal: assert.strictEqual,
+  deepEqual: assert.deepStrictEqual,
+  notEqual: assert.notStrictEqual,
+  notDeepEqual: assert.notDeepStrictEqual
+});
+assert.strict.strict = assert.strict;
+
 var objectKeys = Object.keys || function (obj) {
   var keys = [];
   for (var key in obj) {