diff --git a/index.js b/index.js
index 4c3943d..47b95f7 100644
--- a/index.js
+++ b/index.js
@@ -7,7 +7,7 @@ const isOfType = type => x => typeof x === type; // eslint-disable-line valid-ty
 const isObjectOfType = type => x => getObjectType(x) === type;
 
 const is = value => {
-	if (value == null) { // eslint-disable-line no-eq-null, eqeqeq
+	if (value === null) {
 		return 'null';
 	}
 
@@ -61,7 +61,7 @@ is.undefined = isOfType('undefined');
 is.null = x => x === null;
 is.string = isOfType('string');
 is.number = isOfType('number');
-is.boolean = isOfType('boolean');
+is.boolean = x => x === true || x === false;
 is.symbol = isOfType('symbol');
 
 is.array = Array.isArray;
@@ -168,4 +168,6 @@ is.domElement = x => {
 				!is.plainObject(x) && propsToCheck.every(prop => prop in x);
 };
 
+is.infinite = x => x === Infinity || x === -Infinity;
+
 module.exports = is;
diff --git a/package.json b/package.json
index b19c355..8ef725c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@sindresorhus/is",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "Type check values: `is.string('🦄') //=> true`",
   "license": "MIT",
   "repository": "sindresorhus/is",
diff --git a/readme.md b/readme.md
index 9662489..cfa849d 100644
--- a/readme.md
+++ b/readme.md
@@ -149,6 +149,9 @@ is.inRange(3, 10);
 
 Returns `true` if `value` is a DOM Element.
 
+##### .infinite(value)
+
+Check if `value` is `Infinity` or `-Infinity`.
 
 ## FAQ
 
diff --git a/test.js b/test.js
index 3be5de6..abadfa3 100644
--- a/test.js
+++ b/test.js
@@ -106,6 +106,10 @@ const types = new Map([
 		document,
 		document.implementation.createDocumentType('svg:svg', '-//W3C//DTD SVG 1.1//EN', 'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'),
 		document.createDocumentFragment()
+	]],
+	['infinite', [
+		Infinity,
+		-Infinity
 	]]
 ]);
 
@@ -129,6 +133,13 @@ const testType = (t, type, exclude) => {
 	}
 };
 
+test('is', t => {
+	t.is(m(null), 'null');
+	t.is(m(undefined), 'undefined');
+
+	// TODO: Expand this to all the supported types. Maybe reuse `testType()` somehow.
+});
+
 test('is.undefined', t => {
 	testType(t, 'undefined', ['nullOrUndefined']);
 });
@@ -142,7 +153,7 @@ test('is.string', t => {
 });
 
 test('is.number', t => {
-	testType(t, 'number', ['nan', 'integer']);
+	testType(t, 'number', ['nan', 'integer', 'infinite']);
 });
 
 test('is.boolean', t => {
@@ -380,3 +391,7 @@ test('is.domElement', t => {
 	testType(t, 'domElement');
 	t.false(m.domElement({nodeType: 1, nodeName: 'div'}));
 });
+
+test('is.infinite', t => {
+	testType(t, 'infinite', ['number']);
+});