Add is.arrayLike() (#26)

index.js

@@ -155,6 +155,9 @@ const typedArrayTypes = new Set([
 ]);
 is.typedArray = x => typedArrayTypes.has(getObjectType(x));
 
+const isValidLength = x => is.safeInteger(x) && x > -1;
+is.arrayLike = x => !is.nullOrUndefined(x) && !is.function(x) && isValidLength(x.length);
+
 is.inRange = (x, range) => {
 	if (is.number(range)) {
 		return x >= Math.min(0, range) && x <= Math.max(range, 0);

readme.md

@@ -160,6 +160,20 @@ Returns `true` for instances created by a ES2015 class.
 
 ##### .typedArray(value)
 
+##### .arrayLike(value)
+
+A `value` is array-like if it is not a function and has a `value.length` that is a safe integer greater than or equal to 0.
+
+```js
+is.arrayLike(document.forms);
+//=> true
+
+function () {
+    is.arrayLike(arguments);
+    //=> true
+}
+```
+
 ##### .inRange(value, range)
 
 Check if `value` (number) is in the given `range`. The range is an array of two values, lower bound and upper bound, in no specific order.

test.js

@@ -392,6 +392,18 @@ test('is.typedArray', t => {
 	t.false(m.typedArray({}));
 });
 
+test('is.arrayLike', t => {
+	(() => {
+		t.true(m.arrayLike(arguments));
+	})();
+	t.true(m.arrayLike([]));
+	t.true(m.arrayLike('unicorn'));
+
+	t.false(m.arrayLike({}));
+	t.false(m.arrayLike(() => {}));
+	t.false(m.arrayLike(new Map()));
+});
+
 test('is.inRange', t => {
 	const x = 3;