Helper function + tests

chartjs · Oct 21, 2018 · bd27842 · bd27842
1 parent edd207f
commit bd27842
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diff --git a/src/helpers/helpers.core.js b/src/helpers/helpers.core.js
@@ -51,6 +51,15 @@ var helpers = {
 		return value !== null && Object.prototype.toString.call(value) === '[object Object]';
 	},
 
+	/**
+	 * Returns true if `value` is a finite number, else returns false
+	 * @param {*} value  - The value to test.
+	 * @returns {Boolean}
+	 */
+	isFinite: function(value) {
+		return (typeof value === 'number' || value instanceof Number) && isFinite(value);
+	},
+
 	/**
 	 * Returns `value` if defined, else returns `defaultValue`.
 	 * @param {*} value - The value to return if defined.

diff --git a/test/specs/helpers.core.tests.js b/test/specs/helpers.core.tests.js
@@ -56,6 +56,24 @@ describe('Chart.helpers.core', function() {
 		});
 	});
 
+	describe('isFinite', function() {
+		it('should return true if value is a finite number', function() {
+			expect(helpers.isFinite(0)).toBeTruthy();
+			// eslint-disable-next-line no-new-wrappers
+			expect(helpers.isFinite(new Number(10))).toBeTruthy();
+		});
+
+		it('should return false if the value is infinite', function() {
+			expect(helpers.isFinite(Number.POSITIVE_INFINITY)).toBeFalsy();
+			expect(helpers.isFinite(Number.NEGATIVE_INFINITY)).toBeFalsy();
+		});
+
+		it('should return false if the value is not a number', function() {
+			expect(helpers.isFinite('a')).toBeFalsy();
+			expect(helpers.isFinite({})).toBeFalsy();
+		});
+	});
+
 	describe('isNullOrUndef', function() {
 		it('should return true if value is null/undefined', function() {
 			expect(helpers.isNullOrUndef(null)).toBeTruthy();