feat: finite/coerce

README.md

@@ -101,6 +101,20 @@ ensureNumber(12); // "12"
 ensureNumber(null); // Thrown TypeError: null is not a number
 ```
 
+#### Finite Number
+
+##### `finite/coerce`
+
+Follows [`number/coerce`](#numbercoerce) additionally rejecting `Infinity` and `-Infinity` values (`null` is returned if given values coerces to them)
+
+```javascript
+const coerceToFinite = require("type/finite/coerce");
+
+coerceToFinite("12"); // 12
+coerceToFinite(Infinity); // null
+coerceToFinite(null); // null
+```
+
 #### Object
 
 _Object_ is assumed to be any non-primitive JavaScript value

finite/coerce.js

@@ -0,0 +1,8 @@
+"use strict";
+
+var coerceToNumber = require("../number/coerce");
+
+module.exports = function (value) {
+	value = coerceToNumber(value);
+	return isFinite(value) ? value : null;
+};

test/finite/coerce.js

@@ -0,0 +1,40 @@
+"use strict";
+
+var assert         = require("chai").assert
+  , coerceToFinite = require("../../finite/coerce");
+
+describe("number/finite/coerce", function () {
+	it("Should return input number", function () {
+		assert.equal(coerceToFinite(123.123), 123.123);
+	});
+	it("Should coerce string", function () { assert.equal(coerceToFinite("12"), 12); });
+	it("Should coerce booleans", function () { assert.equal(coerceToFinite(true), 1); });
+	it("Should coerce number objects", function () {
+		assert.equal(coerceToFinite(new Number(343)), 343);
+	});
+	it("Should coerce objects", function () {
+		assert.equal(coerceToFinite({ valueOf: function () { return 23; } }), 23);
+	});
+
+	it("Should reject infinite number", function () {
+		assert.equal(coerceToFinite(Infinity), null);
+	});
+	it("Should reject NaN", function () { assert.equal(coerceToFinite(NaN), null); });
+
+	if (typeof Object.create === "function") {
+		it("Should not coerce objects with no number representation", function () {
+			assert.equal(coerceToFinite(Object.create(null)), null);
+		});
+	}
+
+	it("Should not coerce null", function () { assert.equal(coerceToFinite(null), null); });
+	it("Should not coerce undefined", function () {
+		assert.equal(coerceToFinite(undefined), null);
+	});
+
+	if (typeof Symbol === "function") {
+		it("Should not coerce symbols", function () {
+			assert.equal(coerceToFinite(Symbol("foo")), null);
+		});
+	}
+});