diff --git a/src/array.js b/src/array.js
index c015cc9f..df69e807 100644
--- a/src/array.js
+++ b/src/array.js
@@ -1,4 +1,8 @@
-export var slice = Array.prototype.slice;
+export default function(x) {
+  return typeof x === "object" && "length" in x
+    ? x // Array, TypedArray, NodeList, array-like
+    : Array.from(x); // Map, Set, iterable, string, or anything else
+}
 
 export function shuffle(array) {
   var m = array.length,
diff --git a/src/pack/enclose.js b/src/pack/enclose.js
index c8dbd2a6..8b1d4d88 100644
--- a/src/pack/enclose.js
+++ b/src/pack/enclose.js
@@ -1,7 +1,7 @@
-import {shuffle, slice} from "../array.js";
+import {shuffle} from "../array.js";
 
 export default function(circles) {
-  var i = 0, n = (circles = shuffle(slice.call(circles))).length, B = [], p, e;
+  var i = 0, n = (circles = shuffle(Array.from(circles))).length, B = [], p, e;
 
   while (i < n) {
     p = circles[i];
diff --git a/src/pack/siblings.js b/src/pack/siblings.js
index 4488126d..05047cfd 100644
--- a/src/pack/siblings.js
+++ b/src/pack/siblings.js
@@ -1,3 +1,4 @@
+import array from "../array.js";
 import enclose from "./enclose.js";
 
 function place(b, a, c) {
@@ -45,7 +46,7 @@ function Node(circle) {
 }
 
 export function packEnclose(circles) {
-  if (!(n = circles.length)) return 0;
+  if (!(n = (circles = array(circles)).length)) return 0;
 
   var a, b, c, n, aa, ca, i, j, k, sj, sk;