[New] support cloning Typed Arrays

.eslintrc

@@ -11,7 +11,7 @@
 		"func-style": [2, "declaration"],
 		"global-require": 1,
 		"max-lines-per-function": 0,
-		"max-statements-per-line": 1,
+		"max-statements-per-line": [1, {"max": 2}],
 		"multiline-comment-style": 0,
 		"no-proto": 0,
 		"no-sparse-arrays": 1,
@@ -27,6 +27,7 @@
 			"rules": {
 				"no-console": 0,
 				"no-plusplus": 0,
+				"no-magic-numbers": 0,
 			},
 		},
 	],

index.js

@@ -1,5 +1,7 @@
 'use strict';
 
+var whichTypedArray = require('which-typed-array');
+
 // TODO: use call-bind, is-date, is-regex, is-string, is-boolean-object, is-number-object
 function toS(obj) { return Object.prototype.toString.call(obj); }
 function isDate(obj) { return toS(obj) === '[object Date]'; }
@@ -49,17 +51,22 @@ function copy(src) {
 			dst = { message: src.message };
 		} else if (isBoolean(src) || isNumber(src) || isString(src)) {
 			dst = Object(src);
-		} else if (Object.create && Object.getPrototypeOf) {
-			dst = Object.create(Object.getPrototypeOf(src));
-		} else if (src.constructor === Object) {
-			dst = {};
 		} else {
-			var proto = (src.constructor && src.constructor.prototype)
-				|| src.__proto__
-				|| {};
-			var T = function T() {}; // eslint-disable-line func-style, func-name-matching
-			T.prototype = proto;
-			dst = new T();
+			var ta = whichTypedArray(src);
+			if (ta) {
+				dst = global[ta].from(src);
+			} else if (Object.create && Object.getPrototypeOf) {
+				dst = Object.create(Object.getPrototypeOf(src));
+			} else if (src.constructor === Object) {
+				dst = {};
+			} else {
+				var proto = (src.constructor && src.constructor.prototype)
+					|| src.__proto__
+					|| {};
+				var T = function T() {}; // eslint-disable-line func-style, func-name-matching
+				T.prototype = proto;
+				dst = new T();
+			}
 		}
 
 		forEach(objectKeys(src), function (key) {

package.json

@@ -15,6 +15,7 @@
 		"in-publish": "^2.0.1",
 		"npmignore": "^0.3.0",
 		"safe-publish-latest": "^2.0.0",
+		"semver": "^6.3.1",
 		"tape": "^5.6.1"
 	},
 	"scripts": {
@@ -89,5 +90,8 @@
 		"ignore": [
 			".github/workflows"
 		]
+	},
+	"dependencies": {
+		"which-typed-array": "^1.1.11"
 	}
 }

test/mutability.js

@@ -1,6 +1,7 @@
 'use strict';
 
 var test = require('tape');
+var semver = require('semver');
 var assert = require('assert');
 var traverse = require('../');
 var deepEqual = require('./lib/deep_equal');
@@ -77,6 +78,20 @@ test('cloneT', function (t) {
 	t.end();
 });
 
+/* global Uint8Array */
+test('cloneTypedArray', { skip: semver.satisfies(process.version, '< 4') }, function (t) {
+	var obj = Uint8Array.from([1]);
+	var res = traverse.clone(obj);
+
+	t.same(obj, res);
+	t.ok(obj !== res);
+	obj.set([2], 0);
+	res.set([3], 0);
+	t.same(obj, Uint8Array.from([2]));
+	t.same(res, Uint8Array.from([3]));
+	t.end();
+});
+
 test('reduce', function (t) {
 	var obj = { a: 1, b: 2, c: [3, 4] };
 	var res = traverse(obj).reduce(function (acc, x) {
@@ -194,6 +209,7 @@ test('deleteRedux', function (t) {
 
 	t.ok(!deepEqual(obj, { a: 1, c: [3, undefined, 5] }));
 
+	// eslint-disable-next-line no-sparse-arrays
 	t.ok(deepEqual(obj, { a: 1, c: [3,, 5] }));
 
 	t.ok(!deepEqual(obj, { a: 1, c: [3, null, 5] }));
@@ -219,7 +235,8 @@ test('deleteMap', function (t) {
 
 	t.ok(deepEqual(res, { a: 1, c: xs }));
 
-	t.ok(deepEqual(res, { a: 1, c: [3,,] })); // eslint-disable-line comma-spacing
+	// eslint-disable-next-line comma-spacing, no-sparse-arrays
+	t.ok(deepEqual(res, { a: 1, c: [3,,] }));
 
 	t.ok(deepEqual(res, { a: 1, c: [3] }));
 
@@ -244,6 +261,7 @@ test('deleteMapRedux', function (t) {
 
 	t.ok(!deepEqual(res, { a: 1, c: [3, 5] }));
 
+	// eslint-disable-next-line no-sparse-arrays
 	t.ok(deepEqual(res, { a: 1, c: [3,, 5] }));
 
 	t.end();

test/typed-array.js

@@ -0,0 +1,14 @@
+'use strict';
+
+var test = require('tape');
+var semver = require('semver');
+var traverse = require('../');
+
+/* global Uint8Array */
+test('traverse an UInt8Array', { skip: semver.satisfies(process.version, '< 4') }, function (t) {
+	var obj = Uint8Array.from('test');
+	var results = traverse(obj).map(function () {});
+	t.same(results, obj);
+	t.end();
+});
+