Add is.empty()

index.js

@@ -163,4 +163,12 @@ is.inRange = (x, range) => {
 
 is.infinite = x => x === Infinity || x === -Infinity;
 
+is.empty = value => {
+	return (
+		((is.string(value) || is.array(value)) && !value.length) ||
+		(!is.map(value) && !is.set(value) && is.object(value) && !Object.keys(value).length) ||
+		((is.map(value) || is.set(value)) && !value.size)
+	);
+};
+
 module.exports = is;

readme.md

@@ -150,6 +150,11 @@ is.inRange(3, 10);
 Check if `value` is `Infinity` or `-Infinity`.
 
 
+##### .empty(value)
+
+Returns `true` if `value` is an empty string, array, object, map, or set.
+
+
 ## FAQ
 
 ### Why yet another type checking module?

test.js

@@ -373,3 +373,26 @@ test('is.inRange', t => {
 test('is.infinite', t => {
 	testType(t, 'infinite', ['number']);
 });
+
+test('is.empty', t => {
+	t.true(m.empty(''));
+	t.false(m.empty('🦄'));
+
+	t.true(m.empty([]));
+	t.false(m.empty(['🦄']));
+
+	t.true(m.empty({}));
+	t.false(m.empty({unicorn: '🦄'}));
+
+	const tempMap = new Map();
+	t.true(m.empty(tempMap));
+
+	tempMap.set('unicorn', '🦄');
+	t.false(m.empty(tempMap));
+
+	const tempSet = new Set();
+	t.true(m.empty(tempSet));
+
+	tempSet.add(1);
+	t.false(m.empty(tempSet));
+});