feat: Add support for primitive object wrappers (fixes #295) (#296)

* Added support for primitive object wrappers (fixes #295)

* Updated tests by instructing ESLint to ignore primitive object wrappers.
Updated readme to reflect the added support for primitive object wrappers.
Updated package.json to include myself as contributor.

* Add Oxford comma.

* Add missing commas.

Co-authored-by: Sebastian Mares <mail@smares.de>
Co-authored-by: Golo Roden <golo.roden@thenativeweb.io>

README.md

@@ -54,7 +54,9 @@ The `boolean` function considers the following values to be equivalent to `true`
 -   `'1'` (string)
 -   `1` (number)
 
-_Please note that if you provide a string, it will be trimmed._
+In addition to the primitive types mentioned above, boolean also supports their object wrappers `Boolean`, `String`, and `Number`.
+
+_Please note that if you provide a `string` or `String` object, it will be trimmed._
 
 All other values, including `undefined` and `null` are considered to be `false`.
 

lib/boolean.ts

@@ -1,17 +1,17 @@
 const boolean = function (value: any): boolean {
-  if (typeof value === 'string') {
-    return [ 'true', 't', 'yes', 'y', 'on', '1' ].includes(value.trim().toLowerCase());
-  }
+  switch (Object.prototype.toString.call(value)) {
+    case '[object String]':
+      return [ 'true', 't', 'yes', 'y', 'on', '1' ].includes(value.trim().toLowerCase());
 
-  if (typeof value === 'number') {
-    return value === 1;
-  }
+    case '[object Number]':
+      return value.valueOf() === 1;
 
-  if (typeof value === 'boolean') {
-    return value;
-  }
+    case '[object Boolean]':
+      return value.valueOf();
 
-  return false;
+    default:
+      return false;
+  }
 };
 
 export { boolean };

package.json

@@ -18,6 +18,10 @@
     {
       "name": "Thomas Schaaf",
       "email": "schaaf@komola.de"
+    },
+    {
+      "name": "Sebastian Mares",
+      "email": "camil.sebastian@mares.email"
     }
   ],
   "main": "build/lib/boolean.js",

test/unit/booleanTests.ts

@@ -31,6 +31,16 @@ suite('boolean', (): void => {
     test('false returns false.', async (): Promise<void> => {
       assert.that(boolean(false)).is.false();
     });
+
+    test('Boolean(true) returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new Boolean(true))).is.true();
+    });
+
+    test('Boolean(false) returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new Boolean(false))).is.false();
+    });
   });
 
   suite('string', (): void => {
@@ -129,6 +139,126 @@ suite('boolean', (): void => {
     test('trims whitespace.', async (): Promise<void> => {
       assert.that(boolean(' true  ')).is.true();
     });
+
+    test('String("true") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('true'))).is.true();
+    });
+
+    test('String("false") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('false'))).is.false();
+    });
+
+    test('String("TRUE") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('TRUE'))).is.true();
+    });
+
+    test('String("FALSE") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('FALSE'))).is.false();
+    });
+
+    test('String("t") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('t'))).is.true();
+    });
+
+    test('String("f") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('f'))).is.false();
+    });
+
+    test('String("T") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('T'))).is.true();
+    });
+
+    test('String("F") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('F'))).is.false();
+    });
+
+    test('String("yes") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('yes'))).is.true();
+    });
+
+    test('String("no") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('no'))).is.false();
+    });
+
+    test('String("YES") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('YES'))).is.true();
+    });
+
+    test('String("NO") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('NO'))).is.false();
+    });
+
+    test('String("y") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('y'))).is.true();
+    });
+
+    test('String("n") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('n'))).is.false();
+    });
+
+    test('String("Y") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('Y'))).is.true();
+    });
+
+    test('String("N") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('N'))).is.false();
+    });
+
+    test('String("on") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('on'))).is.true();
+    });
+
+    test('String("ON") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('ON'))).is.true();
+    });
+
+    test('String("1") returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('1'))).is.true();
+    });
+
+    test('String("0") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('0'))).is.false();
+    });
+
+    test('String("contains-the-letter-t") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('contains-the-letter-t'))).is.false();
+    });
+
+    test('String("contains-the-word-yes") returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('noyesno'))).is.false();
+    });
+
+    test('arbitrary string object wrapper string returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String('123'))).is.false();
+    });
+
+    test('trims whitespace in string object wrapper.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new String(' true  '))).is.true();
+    });
   });
 
   suite('number', (): void => {
@@ -143,5 +273,20 @@ suite('boolean', (): void => {
     test('123 returns false.', async (): Promise<void> => {
       assert.that(boolean(123)).is.false();
     });
+
+    test('Number(1) returns true.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new Number(1))).is.true();
+    });
+
+    test('Number(0) returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new Number(0))).is.false();
+    });
+
+    test('Number(123) returns false.', async (): Promise<void> => {
+      // eslint-disable-next-line no-new-wrappers, unicorn/new-for-builtins
+      assert.that(boolean(new Number(123))).is.false();
+    });
   });
 });