feat: add isValidDate

Ref #46

src/index.d.ts

@@ -160,6 +160,11 @@ declare namespace RamdaAdjunct {
          */
         isDate(val: any): val is Date;
 
+        /**
+         * Checks if value is valid `Date` object.
+         */
+        isValidDate(val: any): val is Date;
+
         /**
          * Checks if value is complement of `Date` object
          */

src/index.js

@@ -26,6 +26,7 @@ import isNotObjLike from './isNotObjLike';
 import isPlainObj from './isPlainObj';
 import isNotPlainObj from './isNotPlainObj';
 import isDate from './isDate';
+import isValidDate from './isValidDate';
 import isNotDate from './isNotDate';
 import isNumber from './isNumber';
 import isNotNumber from './isNotNumber';
@@ -89,6 +90,7 @@ export { default as isPlainObject } from './isPlainObj';
 export { default as isNotPlainObj } from './isNotPlainObj';
 export { default as isNotPlainObject } from './isNotPlainObj'; // alias of isNotPlainObject
 export { default as isDate } from './isDate';
+export { default as isValidDate} from './isValidDate';
 export { default as isNotDate } from './isNotDate';
 export { default as isNumber } from './isNumber';
 export { default as isNotNumber } from './isNotNumber';
@@ -157,6 +159,7 @@ const RA = {
   isNotPlainObj,
   isNotPlainObject: isNotPlainObj,
   isDate,
+  isValidDate,
   isNotDate,
   isNumber,
   isNotNumber,

src/isValidDate.js

@@ -0,0 +1,24 @@
+import { invoker, both, pipe } from 'ramda';
+
+import isDate from './isDate';
+import isNotNaN from './isNotNaN';
+
+/**
+ * Checks if value is valid `Date` object.
+ *
+ * @func isValidDate
+ * @memberOf RA
+ * @since {@link https://char0n.github.io/ramda-adjunct/1.8.0|v1.8.0}
+ * @category Type
+ * @sig * -> Boolean
+ * @param {*} val The value to test
+ * @return {Boolean}
+ * @see {@link RA.isDate|isDate}
+ * @example
+ *
+ * RA.isValidDate(new Date()); //=> true
+ * RA.isValidDate(new Date('a')); //=> false
+ */
+const isValidDate = both(isDate, pipe(invoker(0, 'getTime'), isNotNaN));
+
+export default isValidDate;

test/isValidDate.js

@@ -0,0 +1,30 @@
+import RA from '../src/index';
+import eq from './shared/eq';
+import args from './shared/arguments';
+import Symbol from './shared/Symbol';
+
+describe('isValidDate', function() {
+  it('tests a value for a valid `Date`', function() {
+    eq(RA.isValidDate(new Date()), true);
+
+    eq(RA.isValidDate(new Date('a')), false);
+    eq(RA.isValidDate(Date.now()), false);
+    eq(RA.isValidDate(args), false);
+    eq(RA.isValidDate([1, 2, 3]), false);
+    eq(RA.isValidDate(Object(false)), false);
+    eq(RA.isValidDate(new Error()), false);
+    eq(RA.isValidDate(RA), false);
+    eq(RA.isValidDate(Array.prototype.slice), false);
+    eq(RA.isValidDate({ a: 1 }), false);
+    eq(RA.isValidDate(Object(0)), false);
+    eq(RA.isValidDate(/x/), false);
+    eq(RA.isValidDate(Object('a')), false);
+
+    if (Symbol !== 'undefined') {
+      eq(RA.isValidDate(Symbol), false);
+    }
+
+    eq(RA.isValidDate(null), false);
+    eq(RA.isValidDate(undefined), false);
+  });
+});