fix: update devHelper to add dev warning setting locale before loading

Author: iamkun

src/plugin/devHelper/index.js

@@ -16,6 +16,15 @@ export default (o, c, d) => {
       }
       return oldParse.bind(this)(cfg)
     }
+    const oldLocale = d.locale
+    d.locale = function (preset, object, isLocal) {
+      if (typeof object === 'undefined' && typeof preset === 'string') {
+        if (!d.Ls[preset]) {
+          console.warn(`Guessing you may want to use locale ${preset}, you have to load it before using it. https://day.js.org/docs/en/i18n/loading-into-nodejs`)
+        }
+      }
+      return oldLocale(preset, object, isLocal)
+    }
   }
 }
 

test/plugin/devHelper.test.js

@@ -32,3 +32,9 @@ it('Warning Enable customParseFormat plugin while passing the second format para
   dayjs('2020', 'YYYY')
   expect(consoleSpy).toHaveBeenCalledWith('To parse a date-time string like 2020 using the given format, you should enable customParseFormat plugin first. https://day.js.org/docs/en/parse/string-format')
 })
+
+it('Warning: Setting locale before loading locale', () => {
+  const consoleSpy = jest.spyOn(console, 'warn')
+  dayjs.locale('zh-cn')
+  expect(consoleSpy).toHaveBeenCalledWith('Guessing you may want to use locale zh-cn, you have to load it before using it. https://day.js.org/docs/en/i18n/loading-into-nodejs')
+})