[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,
@@ -27,7 +27,17 @@
 			"rules": {
 				"no-console": 0,
 				"no-plusplus": 0,
+				"no-magic-numbers": 0,
 			},
 		},
+		{
+			"files": [
+				"test/typed-array.js",
+				"test/mutability.js",
+			],
+			"globals": {
+				"Uint8Array": false
+			},
+		}
 	],
 }

index.js

@@ -1,5 +1,8 @@
 'use strict';
 
+var whichTypedArray = require('which-typed-array');
+var taSlice = require('typedarray.prototype.slice');
+
 // 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]'; }
@@ -68,17 +71,22 @@ 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) {
+				return taSlice(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(ownEnumerableKeys(src), function (key) {
@@ -287,6 +295,10 @@ Traverse.prototype.clone = function () {
 	var parents = [];
 	var nodes = [];
 
+	if (whichTypedArray(this.value)) {
+		return taSlice(this.value);
+	}
+
 	return (function clone(src) {
 		for (var i = 0; i < parents.length; i++) {
 			if (parents[i] === src) {

package.json

@@ -91,6 +91,10 @@
 			".github/workflows"
 		]
 	},
+	"dependencies": {
+		"typedarray.prototype.slice": "^1.0.1",
+		"which-typed-array": "^1.1.11"
+	},
 	"engines": {
 		"node": ">= 0.4"
 	}

test/mutability.js

@@ -77,6 +77,19 @@ test('cloneT', function (t) {
 	t.end();
 });
 
+test('cloneTypedArray', { skip: typeof Uint8Array !== 'function' }, function (t) {
+	var obj = new Uint8Array([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, new Uint8Array([2]));
+	t.same(res, new Uint8Array([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 +207,7 @@ 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 +233,8 @@ 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 +259,7 @@ 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 +1,12 @@
+'use strict';
+
+var test = require('tape');
+var traverse = require('../');
+
+test('traverse an Uint8Array', { skip: typeof Uint8Array !== 'function' }, function (t) {
+	var obj = new Uint8Array(4);
+	var results = traverse(obj).map(function () {});
+	t.same(results, obj);
+	t.end();
+});
+