Telephone input

Create telephone inputs in your forms.

Telephone input

Use the telInput() function to create telephone inputs in your forms. It uses the HTML <input type="tel"> element which provides built-in telephone format validation.

---

Basic usage

import { Composer } from "formsmd";

const composer = new Composer({
  id: "my-form"
});

composer.telInput("phone", {
  question: "What is your phone number?"
});

Generates the following Markdown-like syntax:

#! id = my-form

phone = TelInput(
  | question = What is your phone number?
)

Required

Add the required parameter to make the field mandatory:

composer.telInput("phone", {
  question: "What is your phone number?",
  required: true
});

Generates the following Markdown-like syntax:

phone* = TelInput(
  | question = What is your phone number?
)

---

Function overview

The following is the overview of the function:

telInput(name: string, params: object)

Arguments

Name	Type	Description
name	string	A unique name for your form field that you'll use to identify the user's response.*
params	object	An object containing all the configuration parameters for your telephone input field (see the parameters section below for the full list of options).

*Avoid values for the name argument which may be the names of HTML attributes, such as "name", "role", "id", etc. This is because by default, the form's template string is first sanitized using DOMPurify, and these values may be removed to prevent DOM clobbering.

---

Parameters

Shared parameters

These parameters are common to all form fields:

Name	Type	Description
question (required)	string	The main question or label of the form field.
required	true (boolean)	When set, the field becomes required.
description	string	Any extra information that the user may need to fill out the form. Appears right below the question.
fieldSize	"sm"	When set to "sm", the font sizes of the question, description, and answer are made smaller.
labelStyle	"classic"	When set to "classic", the question and description of the form field are made smaller.
subfield	true (boolean)	When set, the question and description of the form field are made smaller. Functionally the same as setting labelStyle to "classic".
disabled	true (boolean)	When set, the input is disabled.
autofocus	true (boolean)	When set, the input will be automatically focused when the parent slide becomes active, or immediately after page load.
id	string	The id attribute of the form field container.
classNames	string[]	The CSS class names of the form field. See the available CSS utility classes.
attrs	Array<{ name: string, value: string }>	Other HTML attributes of the form field. Each attribute has a name and value property.
displayCondition	{ dependencies: string[], condition: string }	Controls when the field is shown. The dependencies lists the fields to watch, and condition is the expression that must be true to show the field. The condition must be a valid Nunjucks expression. See example.

Telephone input specific parameters

Name	Type	Description
placeholder	string	Sets the placeholder attribute of the input.
maxlength	number	If set, this becomes the maximum number of allowed characters in the input.
pattern	string	If set, the input value must match the given pattern.
value	string	If set, this becomes the default value of the input.
country	string	The default country code (e.g., "US", "CA", "GB", etc. Defaults to "US" if not specified. ISO alpha-2 format.
availableCountries	string[]	Array of available country codes (e.g., ["US", "CA", "GB"]).

---

Examples

Telephone input with custom placeholder

composer.telInput("contactPhone", {
  question: "What's your phone number?",
  description: "We'll use this number to contact you if needed",
  placeholder: "[phone]",
  required: true
});

Generates the following Markdown-like syntax:

contactPhone* = TelInput(
  | question = What's your phone number?
  | description = We'll use this number to contact you if needed
  | placeholder = [phone]
)

Telephone input with specific country and available countries

composer.telInput("phoneNumber", {
  question: "Phone number",
  description: "Please provide a UK phone number",
  country: "GB",
  availableCountries: ["GB", "IE"],
  required: true
});

Generates the following Markdown-like syntax:

phoneNumber* = TelInput(
  | question = Phone number
  | description = Please provide a UK phone number
  | country = GB
  | availableCountries = GB, IE
)

Styled telephone input with custom attributes

Add CSS classes and other HTML attributes using the classNames and attrs parameters. Please note, these class names and attributes are added to the <div> or <fieldset> container that contains the actual input field(s).

composer.telInput("phoneNumber", {
  question: "Phone number",
  classNames: ["col-6", "xs:col-6"],
  attrs: [
    { name: "style", value: "font-size: 18px;" }
  ]
});

Generates the following Markdown-like syntax:

[.col-6 .xs:col-6 style="font-size: 18px;"]
phoneNumber = TelInput(
  | question = Phone number
)

Please see the available CSS utility classes.

Conditional display

Conditionally show or hide a telephone input field using the displayCondition parameter. It works as follows:

• dependencies lists the fields to watch.

• condition is the expression that must be true to show the field. This must be a valid Nunjucks expression.

For instance, in the example below, the mobile phone input will only show up if the user indicates they want to receive SMS notifications.

composer.choiceInput("wantSMS", {
  question: "Would you like to receive SMS notifications?",
  required: true,
  choices: ["Yes", "No"]
})

composer.telInput("mobilePhone", {
  question: "Mobile phone number",
  displayCondition: {
    dependencies: ["wantSMS"],
    condition: "wantSMS == 'Yes'"
  }
});

Generates the following Markdown-like syntax:

wantSMS* = ChoiceInput(
  | question = Would you like to receive SMS notifications?
  | choices = Yes, No
)

::: [{$ wantSMS $}]
{% if wantSMS == "Yes" %}
mobilePhone = TelInput(
  | question = Mobile phone number
)
{% endif %}
:::

Notes

• The selected country code is sent separately from the actual phone number during form submission. For example, if we had an input with the name contactNumber, the actual number would be sent under the contactNumber key, while the selected country code would be sent under the contactNumberCountryCode.