fix(toFloat): verify the string can be safely converted to a float (#1227)

This is needed because parseFloat('2020-01-06T14:31:00.135Z') will return 2020, even though it should return NaN. This fixes an issue checking isDivisibleBy('2020-01-06T14:31:00.135Z', 2).

Author: peterdemartini

src/lib/toFloat.js

@@ -1,6 +1,7 @@
-import assertString from './util/assertString';
+import isFloat from './isFloat';
 
 export default function toFloat(str) {
-  assertString(str);
+  if (!isFloat(str)) return NaN;
+
   return parseFloat(str);
 }

test/sanitizers.js

@@ -137,6 +137,7 @@ describe('Sanitizers', () => {
         '2.': 2.0,
         '-2.5': -2.5,
         '.5': 0.5,
+        '2020-01-06T14:31:00.135Z': NaN,
         foo: NaN,
       },
     });

test/validators.js

@@ -2335,6 +2335,8 @@ describe('Validators', () => {
         '',
         '.',
         'foo',
+        '20.foo',
+        '2020-01-06T14:31:00.135Z',
       ],
     });
 
@@ -3187,6 +3189,7 @@ describe('Validators', () => {
         '101',
         'foo',
         '',
+        '2020-01-06T14:31:00.135Z',
       ],
     });
   });