update check error condition

src/fieldState.spec.ts

@@ -76,6 +76,35 @@ describe('FieldState', () => {
     expect(state.value).toBe(initialValue)
     expect(state.touched).toBe(false)
   })
+
+  it('should setError well', async () => {
+    const initialValue = ''
+    const state = new FieldState(initialValue)
+
+    state.setError('')
+    expect(state.hasError).toBe(false)
+    expect(state.error).toBe(undefined)
+    expect(state.ownError).toBe(undefined)
+    expect(state.rawError).toBe(undefined)
+
+    state.setError('123')
+    expect(state.hasError).toBe(true)
+    expect(state.error).toBe('123')
+    expect(state.ownError).toBe('123')
+    expect(state.rawError).toBe('123')
+
+    state.setError({ message: 'mewo3' })
+    expect(state.hasError).toBe(true)
+    expect(state.error).toBe('mewo3')
+    expect(state.ownError).toBe('mewo3')
+    expect(state.rawError).toEqual({ message: 'mewo3' })
+
+    state.reset()
+    expect(state.hasError).toBe(false)
+    expect(state.error).toBe(undefined)
+    expect(state.ownError).toBe(undefined)
+    expect(state.rawError).toBe(undefined)
+  })
 })
 
 describe('FieldState validation', () => {
@@ -386,18 +415,6 @@ describe('FieldState validation', () => {
       expect(state.rawError).toEqual({ message: 'error-object-msg' })
       expect(res).toEqual({ hasError: true, error: 'error-object-msg' })
     })
-
-    it('should work well with sync resolved empty message', async () => {
-      const state = new FieldState('').withValidator(
-        _ => ({ message: '' })
-      )
-
-      const res = await state.validate()
-      expect(state.hasError).toBe(true)
-      expect(state.error).toBe('')
-      expect(state.rawError).toEqual({ message: '' })
-      expect(res).toEqual({ hasError: true, error: '' })
-    })
 
     it('should work well with async resolved', async () => {
       const state = new FieldState('').withValidator(

src/formState.spec.ts

@@ -148,6 +148,45 @@ describe('FormState (mode: object)', () => {
     expect(state.value).toEqual(initialValue)
     expect(state.touched).toBe(false)
   })
+
+  it('should setError well', async () => {
+    const initialValue = { foo: 123 }
+    const state = new FormState({
+      foo: new FieldState(initialValue.foo)
+    })
+
+    state.setError('')
+    expect(state.hasError).toBe(false)
+    expect(state.error).toBe(undefined)
+    expect(state.ownError).toBe(undefined)
+    expect(state.rawError).toBe(undefined)
+
+    state.setError('123')
+    expect(state.hasError).toBe(true)
+    expect(state.error).toBe('123')
+    expect(state.ownError).toBe('123')
+    expect(state.rawError).toBe('123')
+
+    state.setError({ message: 'mewo3' })
+    expect(state.hasError).toBe(true)
+    expect(state.error).toBe('mewo3')
+    expect(state.ownError).toBe('mewo3')
+    expect(state.rawError).toEqual({ message: 'mewo3' })
+
+    state.reset()
+
+    state.$.foo.setError({ message: 'mewo4' })
+    expect(state.hasError).toBe(true)
+    expect(state.error).toBe('mewo4')
+    expect(state.ownError).toBe(undefined)
+    expect(state.rawError).toEqual(undefined)
+
+    state.reset()
+    expect(state.hasError).toBe(false)
+    expect(state.error).toBe(undefined)
+    expect(state.ownError).toBe(undefined)
+    expect(state.rawError).toBe(undefined)
+  })
 })
 
 describe('FormState (mode: object) validation', () => {
@@ -1015,6 +1054,43 @@ describe('FormState (mode: array)', () => {
     expect(state.touched).toBe(false)
   })
 
+  it('should setError well', async () => {
+    const initialValue = ['123']
+    const state = new ArrayFormState(initialValue, v => new FieldState(v))
+
+    state.setError('')
+    expect(state.hasError).toBe(false)
+    expect(state.error).toBe(undefined)
+    expect(state.ownError).toBe(undefined)
+    expect(state.rawError).toBe(undefined)
+
+    state.setError('123')
+    expect(state.hasError).toBe(true)
+    expect(state.error).toBe('123')
+    expect(state.ownError).toBe('123')
+    expect(state.rawError).toBe('123')
+
+    state.setError({ message: 'mewo3' })
+    expect(state.hasError).toBe(true)
+    expect(state.error).toBe('mewo3')
+    expect(state.ownError).toBe('mewo3')
+    expect(state.rawError).toEqual({ message: 'mewo3' })
+
+    state.reset()
+
+    state.$[0].setError({ message: 'mewo4' })
+    expect(state.hasError).toBe(true)
+    expect(state.error).toBe('mewo4')
+    expect(state.ownError).toBe(undefined)
+    expect(state.rawError).toEqual(undefined)
+
+    state.reset()
+    expect(state.hasError).toBe(false)
+    expect(state.error).toBe(undefined)
+    expect(state.ownError).toBe(undefined)
+    expect(state.rawError).toBe(undefined)
+  })
+
   it('should reset well with fields changed', async () => {
     const initialValue = ['123', '456']
     const state = new ArrayFormState(initialValue, v => new FieldState(v))

src/state.ts

@@ -1,7 +1,7 @@
 import { action, autorun, computed, makeObservable, observable, when } from 'mobx'
 import { ValidationRawError, ValidationError, IState, Validation, ValidateResult, ValidateStatus, Validator } from './types'
 import Disposable from './disposable'
-import { applyValidators, isPromiseLike, normalizeRawError, normalizeError } from './utils'
+import { applyValidators, isPromiseLike, normalizeRawError, normalizeError, convertEmptyStringWithWarning } from './utils'
 
 /** Extraction for some basic features of State */
 export abstract class BaseState extends Disposable implements Pick<
@@ -74,7 +74,7 @@ export abstract class ValidatableState<V> extends BaseState implements IState<V>
    * Set error info.
    */
   @action setError(error: ValidationRawError) {
-    this._error = error
+    this._error = convertEmptyStringWithWarning(error)
   }
 
   /** List of validator functions. */

src/utils.spec.ts

@@ -129,9 +129,10 @@ describe('normalizeValidationResult', () => {
 
   it('normalizeError should work well', () => {
     expect(normalizeError(undefined)).toBe(undefined)
-    expect(normalizeError('')).toBe('')
+    expect(normalizeError('')).toBe(undefined)
     expect(normalizeError('foo')).toBe('foo')
     expect(normalizeError({ message: 'mewo' })).toBe('mewo')
+    expect(normalizeError(Error('mewo2'))).toBe('mewo2')
 
     class Foo implements ValidationErrorObject { message = 'mewo' }
     const foo = new Foo()

src/utils.ts

@@ -7,7 +7,6 @@ export function normalizeRawError(err: ValidationResult): ValidationRawError {
   }
 
   if (err === false || err === '' || err === null) {
-    // TODO: print an alert?
     return undefined
   }
 
@@ -18,11 +17,27 @@ export function normalizeError(rawError: ValidationRawError): ValidationError {
   if (isErrorObject(rawError)) {
     return rawError.message
   }
-  return rawError
+
+  return convertEmptyStringWithWarning(rawError)
 }
 
 export function isErrorObject(err: any): err is ValidationErrorObject {
-  return err != null && typeof err === 'object' && 'message' in err
+  if (err != null && typeof err === 'object' && 'message' in err) {
+    if (!err.message) {
+      console.log(err)
+      throw new Error('ValidationErrorObject message property cannot be empty')
+    }
+    return true
+  }
+  return false
+}
+
+export function convertEmptyStringWithWarning<T>(err: T) {
+  if (typeof err === 'string' && err === '') {
+    console.warn('An empty string errs should be replaced with undefined.')
+    return undefined
+  }
+  return err
 }
 
 export function isPromiseLike(arg: any): arg is Promise<any> {