Restricted Input

Allow restricted character sets in input elements.

Demo

Try the latest version of Restricted Input here.

Features

• Disallow arbitrary characters based on patterns
• Maintains caret position
• Format/Update on paste
• Works in IE11+

Development

Install dependencies

nvm use # if you have node version manager installed
npm i

Watch files and run demo server

npm run development

This will start a server on port 3099 which can be overridden with the PORT env var.

Unit tests

The following command will run the linting task and the unit tests.

npm test

Integration tests

We use Browserstack to automate end to end testing on Google Chrome, Firefox, and Microsoft Edge.

First, sign up for a free open source Browserstack account.

Copy the .env.example file to .env

cp .env.example .env

Fill in the BROWSERSTACK_USERNAME and BROWSERSTACK_ACCESS_KEY environmental variables with your credentials:

BROWSERSTACK_USERNAME=username
BROWSERSTACK_ACCESS_KEY=access_key

To run the integration tests on Browserstack:

npm run test:integration

To run tests locally on browsers you do not have installed, you may need to install playwright browsers:

npx playwright install firefox chrome msedge

And the tests are run locally with npm run test:integration:local.

To run only certain tests, add the .only property before running the test:

it.only('does something', function () {

Usage

import RestrictedInput from "restricted-input";

const formattedCreditCardInput = new RestrictedInput({
  element: document.querySelector("#credit-card"),
  pattern: "{{9999}} {{9999}} {{9999}} {{9999}}",
});

Patterns

Patterns are a mixture of Placeholders and PermaChars.

Placeholder

A Placeholder is the part of the pattern that accepts user input based on some restrictions. A placeholder is defined in the pattern using two open curly brackets, the placeholder, followed by two closing curly brackets e.g. {{Abc123}}.

The patterns a Placeholder can be are:

• a single alpha character that matches the alpha regex /[A-Za-z]/. e.g. {{C}} will match one alpha character.
• a single digit that matches the digit regex /[0-9]/. e.g. {{3}} will match one digit.
• a * character that matches /./. e.g. {{*}} will match the next character.

PermaChar

A PermaChar is the part of the pattern that is automatically inserted. PermaChars are defined in the pattern as any characters other than Placeholders.

Example patterns

Some example patterns with behavior are listed:

• 12{{3}}
  • Inserts 12.
  • Waits for a single digit from the user.
• {{A}}BC
  • Waits for a single alpha from the user.
  • Inserts BC.
• ${{*2L}}E
  • Inserts $.
  • Waits for any single character input from the user.
  • Waits for a single digit from the user.
  • Waits for a single alpha from the user.
  • Inserts E.

Paste Event

If an input is changed via a paste event, you may want to adjust the pattern before input formatting occurs. In this case, pass an onPasteEvent callback:

const formattedCreditCardInput = new RestrictedInput({
  element: document.querySelector('#credit-card'),
  pattern: '{{9999}} {{9999}} {{9999}} {{9999}}',
  onPasteEvent: function (payload) {
    var value = payload.unformattedInputValue;

    if (requiresAmexPattern(value)) {
      formattedCreditCardInput.setPattern('{{9999}} {{999999}} {{99999}}')
    } else {
      formattedCreditCardInput.setPattern('{{9999}} {{9999}} {{9999}} {{9999}}')
    }
  })
});

API

options

Key	Type	Description
element	HTMLInputElement or HTMLTextAreaElement	A valid reference to an input or textarea DOM node
pattern	String	Pattern describing the allowed character set you wish for entry into corresponding field. See Patterns.
onPasteEvent	Function (optional)	A callback function to inspect the unformatted value of the input during a paste event. See Paste Event.

Browser Support

Desktop

• Chrome (latest)
• Firefox (17+)
• Safari (8+)
• IE11 (desktop/metro)
• IE10 (desktop/metro)
• IE9

Browsers Where Formatting is Turned Off Automatically

Old versions of Samsung Android browsers are incompatible with formatting. These will not attempt to intercept the values and format the input.

TODO

• Improve jsdoc
• Add example guides/pages