https://kenya-eta.info/js/common-form-validation.js?v=0.1

1(function (global) {
2  'use strict';
3
4  var RULES = {
5    name: { min: 2, max: 70 },
6    subject: { min: 10, max: 100 },
7    message: { min: 20, max: 1500 }
8  };
9
10  var FIELD_LABELS = {
11    name: 'Name',
12    subject: 'Subject',
13    message: 'Message'
14  };
15
16  var EMAIL_REGEX = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
17
18  function toText(value) {
19    if (value === null || value === undefined) {
20      return '';
21    }
22    return String(value).trim();
23  }
24
25  function inRange(value, min, max) {
26    var len = toText(value).length;
27    return len >= min && len <= max;
28  }
29
30  function validateName(value) {
31    var text = toText(value);
32    if (text.length === 0) {
33      return { type: 'empty', message: '' };
34    }
35    if (text.length < RULES.name.min) {
36      return { type: 'min', message: 'Name must be at least ' + RULES.name.min + ' characters.' };
37    }
38    if (text.length > RULES.name.max) {
39      return { type: 'max', message: 'Name must be at most ' + RULES.name.max + ' characters.' };
40    }
41    return null;
42  }
43
44  function validateEmail(value) {
45    var text = toText(value);
46    if (text.length === 0) {
47      return { type: 'empty', message: '' };
48    }
49    if (!EMAIL_REGEX.test(text)) {
50      return { type: 'invalid', message: 'Please enter a valid email address.' };
51    }
52    return null;
53  }
54
55  function validateSubject(value, required) {
56    var text = toText(value);
57    if (text.length === 0) {
58      if (!required) return null;
59      return { type: 'empty', message: '' };
60    }
61    if (text.length < RULES.subject.min) {
62      return { type: 'min', message: 'Subject must be at least ' + RULES.subject.min + ' characters.' };
63    }
64    if (text.length > RULES.subject.max) {
65      return { type: 'max', message: 'Subject must be at most ' + RULES.subject.max + ' characters.' };
66    }
67    return null;
68  }
69
70  function validateMessage(value) {
71    var text = toText(value);
72    if (text.length === 0) {
73      return { type: 'empty', message: '' };
74    }
75    if (text.length < RULES.message.min) {
76      return { type: 'min', message: 'Message must be at least ' + RULES.message.min + ' characters.' };
77    }
78    if (text.length > RULES.message.max) {
79      return { type: 'max', message: 'Message must be at most ' + RULES.message.max + ' characters.' };
80    }
81    return null;
82  }
83
84  function getLimitMessage(fieldName, value) {
85    var fieldRule = RULES[fieldName];
86    var fieldLabel = FIELD_LABELS[fieldName];
87    var text = toText(value);
88
89    if (!fieldRule || !fieldRule.max || !fieldLabel) {
90      return '';
91    }
92
93    if (text.length >= fieldRule.max) {
94      return fieldLabel + ' character limit reached (' + fieldRule.max + ').';
95    }
96
97    return '';
98  }
99
100  function validateForm(values, options) {
101    var opts = options || {};
102    var subjectRequired = !!opts.subjectRequired;
103
104    var errors = {
105      name: validateName(values && values.name),
106      email: validateEmail(values && values.email),
107      subject: validateSubject(values && values.subject, subjectRequired),
108      message: validateMessage(values && values.message)
109    };
110
111    var isValid = !errors.name && !errors.email && !errors.subject && !errors.message;
112
113    var messages = {
114      name: errors.name ? errors.name.message : '',
115      email: errors.email ? errors.email.message : '',
116      subject: errors.subject ? errors.subject.message : '',
117      message: errors.message ? errors.message.message : ''
118    };
119
120    return {
121      isValid: isValid,
122      errors: errors,
123      messages: messages,
124      rules: RULES
125    };
126  }
127
128  global.CommonFormValidation = {
129    rules: RULES,
130    validateName: validateName,
131    validateEmail: validateEmail,
132    validateSubject: validateSubject,
133    validateMessage: validateMessage,
134    getLimitMessage: getLimitMessage,
135    validateForm: validateForm
136  };
137})(window);