Enable strict parsing for auto-detecting time fields

Fixes #202

Author: marcusolsson

src/detectFieldType.test.ts

@@ -25,6 +25,10 @@ test('nullable iso8601 gets parsed as time', () => {
   expect(detectFieldType(['2006-01-02T15:06:13Z', null])).toStrictEqual('time');
 });
 
+test('regression for #202', () => {
+  expect(detectFieldType(['foo bar 1.1'])).toStrictEqual('string');
+});
+
 test('floating-point numbers with string length 13 get parsed as number', () => {
   expect(detectFieldType([12.0000000003, 72.0000000001])).toStrictEqual('number');
 });

src/detectFieldType.ts

@@ -1,5 +1,5 @@
 import { FieldType } from '@grafana/data';
-import dayjs from 'dayjs';
+import moment from 'moment';
 
 /**
  * Detects the field type from an array of values.
@@ -13,7 +13,7 @@ export const detectFieldType = (values: any[]): FieldType => {
   // If all values are valid ISO 8601, then assume that it's a time field.
   const isValidISO = values
     .filter((value) => value !== null)
-    .every((value) => value.length >= 10 && dayjs(value).isValid());
+    .every((value) => moment(value, ['YYYY-MM-DD', moment.defaultFormat], true).isValid());
   if (isValidISO) {
     return FieldType.time;
   }