Devel

.eslintrc

@@ -19,6 +19,7 @@
     "keyword-spacing": ["warn", {"after": true}],
     "jsx-quotes": ["warn", "prefer-double"],
     "no-extra-boolean-cast": "off",
+    "no-console": 0,
     "no-multi-spaces": "warn",
     "no-spaced-func": "warn",
     "no-unused-vars": "warn",

README.md

@@ -156,7 +156,7 @@ If there are many rules, the their priority will be similar to the array order.
 
 ## Api
 
-### constructor({FieldsDescription}, errorsStorageName = 'validationStorage')
+### constructor({FieldsDescription}, validationStorageName = 'validationStorage')
 Describe in the constructor all the fields, that you will check. Like in the [example](#form-example).
 By default all validation data will be added to the 'validationStorage' key of the state object. You can change it, if you need. You can describe for each field [1 or many rules](#creating-validation-rules).
 
@@ -228,7 +228,11 @@ this.setState(
 Use this method inside the render function, like in the [example](#form-example). It will return the object with fields keys and their error messages. If the field is valid there will be an empty error string.
 
 ### isFormValid({state})
-Use this method to check, if the field is valid. It will return true, if all the fields in the form are valid. See the [example](#form-example)
+Use this method to check, if the form is valid. It will return true, if all the fields in the form are valid. See the [example](#form-example)
+
+### isFieldValid({state}, fieldName)
+Use this method to check, if particular field is valid. Returns true if it is valid, false otherwise
+
 
 ## Compatibility 
 This package id fully compatible with the React v.16, because it uses state updater functions inside.

__tests__/index.test.js

@@ -190,5 +190,27 @@ describe('Unit tests for Validation class', () => {
       state = Object.assign({}, state, result);
       expect(Validator.isFormValid(state)).toEqual(true);
     });
+
+    test('Validator.isFieldValid(state,"login") method returns false', () => {
+      const updater = Validator.validate({
+        login: ''
+      });
+      const result = updater(state);
+      state = Object.assign({}, state, result);
+      expect(Validator.isFieldValid(state, 'login')).toEqual(false);
+    });
+
+    test('Validator.isFieldValid(state,"password") method returns true', () => {
+      expect(Validator.isFieldValid(state, 'password')).toEqual(true);
+    });
+
+    test('Validator.isFieldValid(state,"login") method returns true after login field became validated', () => {
+      const updater = Validator.validate({
+        login: 'peterson'
+      });
+      const result = updater(state);
+      state = Object.assign({}, state, result);
+      expect(Validator.isFieldValid(state, 'login')).toEqual(true);
+    });
   });
 });

src/index.js

@@ -39,7 +39,7 @@ class Validation {
 
   constructor(
     fields: FieldsDescription,
-    errorsStorageName: string = 'validationStorage'
+    validationStorageName: string = 'validationStorage'
   ) {
     if (typeof fields !== 'object') {
       throw new Error('Invalid fields parameter for fields, must be object');
@@ -48,7 +48,7 @@ class Validation {
     this.fields = allRulesInArrays(fields);
     this.fieldsToValidateList = [];
     this.fieldsToShowErrors = [];
-    this.storage = errorsStorageName;
+    this.validationStorageName = validationStorageName;
     this.statuses = [
       'validation-passed',
       'prevalidation-failed',
@@ -94,7 +94,7 @@ class Validation {
     );
 
     return Object.assign(state, {
-      [this.storage]: toStorage
+      [this.validationStorageName]: toStorage
     });
   }
 
@@ -129,7 +129,7 @@ class Validation {
       // computing the state as a merge from prevState and stateUpdates to do the right validation
       let state = Object.assign({}, prevState, stateUpdates || {});
       // clean the service error storage field, so the rule will have no acces to it
-      delete state[this.storage];
+      delete state[this.validationStorageName];
       keysToValidate.map(key => {
         if (this.fields[key]) {
           toStorage[key] = this._validateField(
@@ -142,7 +142,11 @@ class Validation {
       });
       this.fieldsToShowErrors = [];
       return Object.assign(stateUpdates || {}, {
-        [this.storage]: Object.assign({}, prevState[this.storage], toStorage)
+        [this.validationStorageName]: Object.assign(
+          {},
+          prevState[this.validationStorageName],
+          toStorage
+        )
       });
     };
   }
@@ -185,7 +189,7 @@ class Validation {
     const validationFailed = this.statuses[2];
 
     keys.map(key => {
-      const current = state[this.storage][key];
+      const current = state[this.validationStorageName][key];
       // check every rule
       for (let i = 0; i < current.length; i++) {
         if (current[i] === validationFailed) {
@@ -202,15 +206,15 @@ class Validation {
   }
 
   isFormValid(state: Object): boolean {
-    const errors = state[this.storage];
-    if (typeof errors !== 'object') {
-      throw new Error('Invalid errors parameter for fields, must be object');
+    const storage = state[this.validationStorageName];
+    if (typeof storage !== 'object') {
+      throw new Error('Invalid fieldsMappedToStatuses object, must be object');
     }
 
-    const keys = Object.keys(errors);
+    const keys = Object.keys(storage);
     const [validationPassed] = this.statuses;
     for (let i = 0; i < keys.length; i++) {
-      const currentStatuses = errors[keys[i]];
+      const currentStatuses = storage[keys[i]];
       for (let j = 0; j < currentStatuses.length; j++) {
         if (currentStatuses[j] !== validationPassed) {
           return false;
@@ -220,6 +224,27 @@ class Validation {
     // if form valid return true
     return true;
   }
+
+  isFieldValid(state: Object, fieldName: string): boolean {
+    const storage = state[this.validationStorageName];
+    if (typeof storage !== 'object') {
+      throw new Error('Invalid storage object, must be object');
+    }
+    const fieldStatuses = storage[fieldName];
+    if (!fieldStatuses) {
+      // TODO: how to disable warnings in production
+      console.warn("Attempt to validate field that doesn't exist");
+      return false;
+    }
+
+    const [validationPassed] = this.statuses;
+    for (let j = 0; j < fieldStatuses.length; j++) {
+      if (fieldStatuses[j] !== validationPassed) {
+        return false;
+      }
+    }
+    return true;
+  }
 }
 
 const allRulesInArrays = (