validators()

validators checks one value against a named rule and returns whether it's valid.

validators(value, name, options)

Parameter	Description
value	The value to check: text, a number, a Date, or null
name	A base rule, a preset, or null to check only the options
options	Optional. The options that add checks or change messages

Returns

validators returns one of these objects:

{ valid: true }
{ valid: false, code, message }

The code names the check that failed, and the message is the text to show. When a preset's own check fails, the code is the preset's name. When a check that you added fails, the code is that option's name. For every code and its default message, see Error codes and messages.

Throws

validators throws an error for a wrong call:

• An unknown rule name or option
• A regex that uses \d, \w, or \s, or that doesn't compile
• An unknown timezone
• A date bound that isn't a date, "today", "now", or { addDays: n }

Base rules

A base rule is a general kind of check. You narrow a base rule with options. The package has seven base rules:

Rule	Accepts
alphaNumeric	Letters and digits
lettersOnly	Letters and spaces
numbersOnly	Digits only, checked as characters: "007" passes, and "12.5" and "-3" fail
number	A number value, such as -18.5, 12, or 0.75
email	An address in the form name@domain.tld
password	Eight or more characters, with an upper-case letter, a lower-case letter, a digit, and one of @$!%*?&
date	2026-10-07, 2026-10-07 14:30:00 (UTC), ISO 8601 text with T, Z, or +05:30, or a Date; impossible dates such as 2026-02-30 fail

Presets

A preset is a base rule, a pattern, or both, with options already set, saved under one name. Your options override the preset's options, so validators(v, "mobile", { length: 12 }) accepts 12 digits. The package has 16 presets:

Preset	Accepts
integer	A number with no decimals
positiveNumber	A number greater than 0
amount	A number of 0 or more, with up to two decimals
weight	A number of 0 or more, with up to three decimals
percentage	A number from 0 to 100, with up to two decimals
decimalUpTo2	A number of 0 or more, with up to two decimals
decimalUpTo6	A number of 0 or more, with up to six decimals
mobile	A 10-digit mobile number
pincode	A six-digit Postal Index Number (PIN) code
vehicleNumber	A vehicle registration number, such as KA01AB1234, DL1C1234, or the Bharat (BH) series 22BH1234AA
gstin	A Goods and Services Tax Identification Number (GSTIN), such as 27ABCDE1234F1Z5
pan	A Permanent Account Number (PAN), such as ABCDE1234F
ifsc	An Indian Financial System Code (IFSC), such as HDFC0001234
iec	An Importer-Exporter Code (IEC) of 10 letters or digits
pastDate	A date that isn't after today
futureDate	A date that isn't before today

The ID presets pan, gstin, ifsc, iec, and vehicleNumber expect upper case. Pair them with the formatter of the same name. For details, see Format and validate a form field.

Options

validators takes these options:

Option	Meaning
required	When true, a blank value fails
label	The field name used in the required message
message	Replaces the default message of every check except required
length	Exactly this many characters
minLength	At least this many characters
maxLength	At most this many characters
minValue	The smallest number allowed, checked only when the value is a number
maxValue	The largest number allowed, checked only when the value is a number
decimalPlaces	At most this many digits after the decimal point; 0 allows none
regex	A pattern the whole value must match, such as "^[A-Z]{4}[0-9]{7}$"; see Patterns
minDate	The earliest date allowed, inclusive
maxDate	The latest date allowed, inclusive
after	A date the value must be after, exclusive
before	A date the value must be before, exclusive
timezone	The zone for "today" and for dates in messages: "Asia/Kolkata" (default), "UTC", or an offset such as "+05:30"
now	The current time to compare against, instead of the clock; use it in tests

Order of checks

The checks run in this order, and the first failure is returned:

1. required
2. The rule
3. regex
4. decimalPlaces
5. minValue and maxValue
6. length, minLength, and maxLength
7. The date bounds

Blank values

A blank value passes every check except required, so optional fields need nothing special. A blank value is null, undefined, empty or whitespace-only text, or [].

Date bounds

The minDate, maxDate, after, and before options each accept these values:

• A date, such as "2026-10-07", "2026-10-07 14:30:00", ISO 8601 text, or a Date
• "today", the calendar day in timezone
• "now", the current instant
• { addDays: n }, today plus n days, where a negative n counts back
• Another field's value, such as validators(bidEnd, "date", { after: bidStart })

When either side is a plain date, the package compares calendar days in timezone. When both sides carry a time, it compares instants.

Patterns

The regex option takes text, not a JavaScript /regex/, so the same rule can sit in a JSON config and be sent to a Python service. The value must match the whole pattern.

validators("ABCD1234567", null, { regex: "^[A-Z]{4}[0-9]{7}$", message: "Enter a valid container number" })

important

Don't use \d, \w, or \s in a pattern; the call throws an error if you do. Python reads them differently: its \d matches every Unicode digit. Write [0-9], [A-Za-z0-9_], and [ \t] instead.

Use only pattern features that both languages share: character classes, groups, {n,m}, |, and lookaheads.

Examples

The following examples show common calls:

validators("560001", "pincode")                  // { valid: true }
validators("56001", "pincode")                   // { valid: false, code: "pincode", message: "Enter a valid 6-digit PIN code" }
validators("", "pincode", { required: true, label: "Delivery PIN" })   // message: "Delivery PIN is required"
validators("abcde1234f", "pan")                  // message: "Enter a valid PAN (e.g. ABCDE1234F)"
validators("0.5", "number", { decimalPlaces: 3, minValue: 1 })         // message: "Minimum value is 1"
validators("0", "integer", { minValue: 1 })      // code: "minValue"
validators("2026-10-07", "date", { minDate: "today", maxDate: { addDays: 30 } })
validators("Al", null, { minLength: 3 })         // { valid: false, code: "minLength", message: "Minimum 3 characters required" }

Related topics

• Format and validate a form field
• Error codes and messages
• formatters()