Helpers

Module with various helper methods providing basic (seed-dependent) operations useful for implementing faker methods.

Overview

A particularly helpful method is {{$helpers.arrayElement(['abc','123'])}} which returns a random element from an array. This is useful when adding custom data that Faker doesn't contain.

A number of methods can generate strings according to various patterns: {{$helpers.replaceSymbols('##??**')}} and {{$helpers.fromRegExp('[A-Z0-9]{4}-[A-Z0-9]{4}')}}.

---

arrayElement

Returns random element from the given array.

Parameters

Name	Type	Default	Description
array	T[]		The array to pick the value from.

Returns: T

Examples

{{$helpers.arrayElement(['cat','dog','mouse'])}}  // 'cat'

---

arrayElements

Returns a subset with random elements of the given array in random order.

Parameters

Name	Type	Default	Description
array	T[]		The array to pick the value from.
max	number		The maximum number of elements to pick.
min	number		The minimum number of elements to pick.

Returns: T

Examples

{{$helpers.arrayElements(['cat','dog','mouse'])}}  // '["cat"]'

{{$helpers.arrayElements(['1','2','3','4'])}}  // '["4"]'

---

fromRegExp

Generates a string matching the given regex like expressions.

This function doesn't provide full support of actual RegExp. Features such as grouping, anchors and character classes are not supported. If you are looking for a library that randomly generates strings based on RegExps, see randexp.js

Supported patterns:

• x{times} => Repeat the x exactly times times.
• x{min,max} => Repeat the x min to max times.
• [x-y] => Randomly get a character between x and y (inclusive).
• [x-y]{times} => Randomly get a character between x and y (inclusive) and repeat it times times.
• [x-y]{min,max} => Randomly get a character between x and y (inclusive) and repeat it min to max times.
• [^...] => Randomly get an ASCII number or letter character that is not in the given range. (e.g. [^0-9] will get a random non-numeric character).
• [-...] => Include dashes in the range. Must be placed after the negate character ^ and before any character sets if used (e.g. [^-0-9] will not get any numeric characters or dashes).
• /[x-y]/i => Randomly gets an uppercase or lowercase character between x and y (inclusive).
• x? => Randomly decide to include or not include x.
• [x-y]? => Randomly decide to include or not include characters between x and y (inclusive).
• x* => Repeat x 0 or more times.
• [x-y]* => Repeat characters between x and y (inclusive) 0 or more times.
• x+ => Repeat x 1 or more times.
• [x-y]+ => Repeat characters between x and y (inclusive) 1 or more times.
• . => returns a wildcard ASCII character that can be any number, character or symbol. Can be combined with quantifiers as well. Parameters

Name	Type	Default	Description
pattern	string | RegExp		The template string/RegExp to generate a matching string for.

Returns: string

Throws: If min value is more than max value in quantifier, e.g. #{10,5}. If an invalid quantifier symbol is passed in.

Examples

{{$helpers.fromRegExp('#{5}')}} // '#####'

{{$helpers.fromRegExp('#{2,9}')}} // '#######'

{{$helpers.fromRegExp('[1-7]')}} // '5'

{{$helpers.fromRegExp('#{3}test[1-5]')}} // '###test3'

{{$helpers.fromRegExp('[0-9a-dmno]')}} // '5'

{{$helpers.fromRegExp('[^a-zA-Z0-8]')}} // '9'

{{$helpers.fromRegExp('[a-d0-6]{2,8}')}} // 'a0dc45b0'

{{$helpers.fromRegExp('[-a-z]{5}')}} // 'a-zab'

{{$helpers.fromRegExp('/[A-Z0-9]{4}-[A-Z0-9]{4}/')}}// '/RUQN-KAVE/'

{{$helpers.fromRegExp('/[A-Z]{5}/i')}} // '/EJORS/i'

{{$helpers.fromRegExp('/.{5}/')}} // '/...../'

{{$helpers.fromRegExp('/Joh?n/')}} // '/Jon/'

{{$helpers.fromRegExp('/ABC*DE/')}} // '/ABCDE/'

{{$helpers.fromRegExp('/bee+p/')}} // '/beep/'

---

rangeToNumber

Helper method that converts the given number or range to a number.

Parameters

Name	Type	Default	Description
max	number		The maximum value for the range.
min	number		The minimum value for the range.

Returns: number

Examples

{{$helpers.rangeToNumber}}  // '6'
{{$helpers.rangeToNumber(min=1,max=10)}}  // '1'

---

replaceCreditCardSymbols

Replaces the symbols and patterns in a credit card schema including Luhn checksum.

Parameters

Name	Type	Default	Description
string	string	'6453-####-####-####-###L'	The credit card format pattern.
symbol	string	'#'	The symbol to replace with a digit.

Returns: string

Examples

{{$helpers.replaceCreditCardSymbols}}  // '6453-1529-4797-6717-3847'

{{$helpers.replaceCreditCardSymbols(string='1234-[4-9]-##!!-L')}}  // '1234-7-5096-4'

---

replaceSymbols

Parses the given string symbol by symbols and replaces the placeholder appropriately.

• # will be replaced with a digit (0 - 9).
• ? will be replaced with an upper letter ('A' - 'Z')
• and * will be replaced with either a digit or letter.

Parameters

Name	Type	Default	Description
string	string		The template string to parse.

Returns: string

Examples

{{$helpers.replaceSymbols('##??**')}}  // '24BTX6'

{{$helpers.replaceSymbols('#####')}}  // '17608'

{{$helpers.replaceSymbols('?????')}}  // 'SYJON'

{{$helpers.replaceSymbols('*****')}}  // 'CZ436'

{{$helpers.replaceSymbols('Your pin is: #?*#?*')}}  // 'Your pin is: 7UU5NK'

---

slugify

Slugifies the given string. For that all spaces ( ) are replaced by hyphens (-) and most non word characters except for dots and hyphens will be removed.

Parameters

Name	Type	Default	Description
string	string		The input to slugify.

Returns: string

Examples

{{$helpers.slugify('abc 123')}}  // 'abc-123'

{{$helpers.slugify('Hello world!')}}  // 'Hello-world'

---

slugify

Slugifies the given string. For that all spaces ( ) are replaced by hyphens (-) and most non word characters except for dots and hyphens will be removed.

Parameters

Name	Type	Default	Description
string	string		The input to slugify.

Returns: string

Examples

{{$helpers.slugify('abc 123')}}  // 'abc-123'
{{$helpers.slugify('Hello world!')}}  // 'Hello-world'

---