react-phone-number-input

International phone number <input/> for React.

See Demo

Install

npm install react-phone-number-input --save

Alternatively, one could include it on a web page directly via a <script/> tag.

Use

This package exports two variants of the input component, depending on what you prefer:

• With country select — A phone number input field with a country select on the left side.
  • This is the most straightforward and easy-to-use one.
  • Provides everything out-of-the-box:
    • CSS styles.
    • Country flags.
    • Country labels in different languages.
• Without country select — Just the phone number input field.
  • This is the "bare-bones" variant.
  • For those who like minimalism or would like to build their own.

With country select

"With country select" component requires only two properties: value and onChange(value).

// CSS styles
import 'react-phone-number-input/style.css'

import PhoneInput from 'react-phone-number-input'

function Example() {
  const [value, setValue] = useState()
  return (
    <PhoneInput
      placeholder="Enter phone number"
      value={value}
      onChange={setValue}
    />
  )
}

More on the properties:

• onChange

  • When the user types something in the input field, onChange function will be called, with its argument being the parsed phone number (in E.164 format). For example, if the user chooses "United States" and enters (213) 373-4253 in the input field, onChange function will be called with the argument "+12133734253".
  • When the user clears the input field, onChange function will be called with undefined as an argument. Perhaps null would've been better, but historically it was decided to be undefined.

• value

  • The input value (in E.164 format). Example: "+12133734253".
  • Any "falsy" value — for example, undefined, null, or empty string "" — will be treated as "no value".

• defaultCountry (optional)

  • Specifies the initially-selected country. When provided, it must be a two-letter country code. Example: "US" (United States).

• onCountryChange (optional)

  • When the user selects a different country, onCountryChange function will be called with the new country code as an argument.

• For other supported properties, see the list of all available props.

• Any unknown properties, such as placeholder, will be passed through to the underlying <input/> component.

CSS

"With country select" component requires including style.css stylesheet on the page.

All CSS class names start with .PhoneInput prefix in order to not conflict with the application styles.

The following "status modifier" CSS classes are available:

• .PhoneInput--focus for :focus state
• .PhoneInput--disabled for :disabled state
• .PhoneInput--readOnly for [readonly] state

The stylesheet uses native CSS variables for convenience. Native CSS variables have been supported in all modern browsers for a long time now, but ancient ones like Internet Explorer don't support them. If compatibility with such ancient browsers is required, one could use a CSS transformer like PostCSS with a "CSS custom properties" plugin.

Some of the CSS variables of interest:

• --PhoneInputCountryFlag-height — Flag icon height.
• --PhoneInputCountryFlag-borderColor — Flag icon outline color.
• --PhoneInputCountrySelectArrow-color — Country select arrow color.
• --PhoneInputCountrySelectArrow-opacity — Country select arrow opacity (when not :focused).
• --PhoneInput-color--focus — Flag icon :focus outline color, and also country select arrow :focus color.
• …

Without country select

"Without country select" component is just a minimal "bare-bones" phone number <input/>, without any CSS.

import PhoneInput from 'react-phone-number-input/input'

function Example() {
  // `value` holds the parsed phone number (in E.164 format).
  // When the input is empty, or when there's not enough digits, value is `undefined`.
  //
  // Example: "+12133734253".
  //
  const [value, setValue] = useState()

  // Specifying a `country` only allows input of phone numbers belonging to that specific country.
  // Not specifying a `country` only allows input of any phone number in international format
  // (i.e. starting with a "+").
  //
  return (
    <PhoneInput
      country="US"
      value={value}
      onChange={setValue}
    />
  )
}

Available properties:

• country: string? — If country is specified then it only allows input of phone numbers that belong to that specific country. When specified, the value must be a supported country code. Example: country="US".

• defaultCountry: string? — If defaultCountry is specified then phone numbers can be input either in "international" format for any country or in "national" format for that specific country. Basically, it imposes a country restriction but only on phone numbers in "national" format while allowing any phone numbers in "international" format. In other words: "When the country is not specified in the phone number itself, assume it to be ... by default". When specified, the value must be a supported country code. Example: defaultCountry="US".

• international: boolean? — Controls which phone number format is allowed: "international" or "national" (or both). Set to true to only allow "international" format. Set to false to only allow "national" format.

  • When international property is not explicitly specified, its default value will be determined based on the values of other properties such as country or defaultCountry:
    • When country is specified, the default value of international property is false, meaning that the phone number can only be input in "national" format for that country.
    • When defaultCountry is specified, the phone number could be input either in "international" format or in "national" format for the defaultCountry, so the default value of international property stays undefined.
    • When no country or defaultCountry are specified, the phone number can only be input in "international" format (without any country restrictions), so the default value of the international property is true.
  • When country is specified and international property is explicitly set to true, the phone number can only be input in "international" format for that country.
    • In that case, by default, the "country calling code" part — for example, "+1" when country is "US" — is not included in the input field.
      • Example: if country is "US" and international property is true then the phone number can only be input in "international" format for US, without the leading "+1" part, so it would look like "213 373 4253" rather than "+1 213 373 4253".
      • This is done intentionally so that a developer could build their own multi-country phone number input component where the "country calling code" part like "+1" is selectable separately before the main input field.
      • To disable this behavior, set withCountryCallingCode property to true, and the "country calling code" part like "+1" will be part of the input field, but be aware that it still won't be editable because otherwise it would contradict the country property.
        • Example: if country is "US" and international property is true and withCountryCallingCode property is true then the phone number can only be input in "international" format for US, with the fixed leading "+1" part, so it would look like "+1 213 373 4253".

• withCountryCallingCode: boolean? — If country is specified and international property is true then the phone number can only be input in "international" format for that country. By default, the "country calling code" part — for example, +1 when country is US — is not included in the input field. To change that, set withCountryCallingCode property to true, and it will include the "country calling code" part in the input field, although it will still be non-editable. See the demo for an example.

• useNationalFormatForDefaultCountryValue: boolean? — By default, when defaultCountry is defined and the initial phone number belongs to the defaultCountry, that initial phone number is formatted in "national" format. A developer might rather prefer it to use "international" format for that, in which case set useNationalFormatForDefaultCountryValue property value to false.

• value: string? — Phone number value. Examples: undefined, "+12133734253".

• onChange(value: string?) — Updates the value (to undefined in case it's empty).

• inputComponent: component? — Custom input component.

  • By default, it's a generic DOM <input/> component.
  • Any custom input component implementation must use React.forwardRef() to "forward" ref to the underlying "core" <input/> component.
  • Receives properties:
    • value: string
    • onChange(event: Event)
    • Any other properties that were passed to <PhoneInput/> and aren't specifically handled by this library. For example, type="tel", autoComplete="tel", etc.

• smartCaret: boolean? — When the user attempts to insert a digit somewhere in the middle of a phone number, the caret position is moved right before the next available digit skipping any punctuation in between. This is called "smart" caret positioning. Another case would be the phone number format changing as a result of the user inserting the digit somewhere in the middle, which would require re-positioning the caret because all digit positions have changed. This "smart" caret positioning feature can be turned off by passing smartCaret={false} property: use it in case of any possible issues with caret position during phone number input.

See the demo for the examples.

If you're an "advanced" user who'd like to pass their custom libphonenumber-js metadata, use react-phone-number-input/input-core component instead — it accepts metadata property.

This package also exports getCountries() and getCountryCallingCode(country) functions that a developer could use to construct their own custom country select. Such custom country <select/> could be used alongside the "without country select" <input/> component.

How to create a custom country <select/>

import PropTypes from 'prop-types'
import { getCountries, getCountryCallingCode } from 'react-phone-number-input'

const CountrySelect = ({ value, onChange, labels, ...rest }) => (
  <select
    {...rest}
    value={value}
    onChange={event => onChange(event.target.value || undefined)}>
    <option value="">
      {labels['ZZ']}
    </option>
    {getCountries().map((country) => (
      <option key={country} value={country}>
        {labels[country]} +{getCountryCallingCode(country)}
      </option>
    ))}
  </select>
)

CountrySelect.propTypes = {
  value: PropTypes.string,
  onChange: PropTypes.func.isRequired,
  labels: PropTypes.objectOf(PropTypes.string).isRequired
}

Use:

import PhoneInput from 'react-phone-number-input/input'
import en from 'react-phone-number-input/locale/en'
import CountrySelect from './CountrySelect'

function Example() {
  const [country, setCountry] = useState('US')
  const [value, setValue] = useState()
  return (
    <div>
      <CountrySelect
        labels={en}
        value={country}
        onChange={setCountry}/>
      <PhoneInput
        country={country}
        value={value}
        onChange={setValue}/>
    </div>
  )
}

React Native

This package also includes a React Native version of a "without country select" component. Post bug reports and suggestions in the feedback thread.

import React, { useState } from 'react'
import PhoneInput from 'react-phone-number-input/react-native-input'

function Example() {
  const [value, setValue] = useState()
  return (
    <PhoneInput
      style={...}
      country="US"
      value={value}
      onChange={setValue}
    />
  )
}

It accepts the same properties as the web version of "without country select" component, with the following differences:

• smartCaret: boolean? property is not supported because "smart caret" positioning feature is not implemented in the React Native component.

• inputComponent: component? — By default, it renders a generic <TextInput/>. A custom input component can be passed. Such custom input component must forwardRef() to the underlying input field. The input component receives properties:

  • value: string
  • onChangeText(value: string)
  • all the "rest" of the properties that're not handled by this library, like keyboardType="phone-pad", autoCompleteType="tel", etc.

Validation

To validate the phone number input value, use the exported isPossiblePhoneNumber(value) function.

import { isPossiblePhoneNumber } from 'react-phone-number-input'

const isValid = (value) => Boolean(value) && isPossiblePhoneNumber(value)

What to do next with the returned boolean value is up to each different application. Most applications use frameworks like react-hook-form or formik or a gazillion of other ones. Those frameworks each have their own way of setting up validation.

Utility

This package exports several utility functions.

formatPhoneNumber(value: string): string

Formats value as a "local" phone number.

import { formatPhoneNumber } from 'react-phone-number-input'
formatPhoneNumber('+12133734253') === '(213) 373-4253'

formatPhoneNumberIntl(value: string): string

Formats value as an "international" phone number.

import { formatPhoneNumberIntl } from 'react-phone-number-input'
formatPhoneNumberIntl('+12133734253') === '+1 213 373 4253'

isPossiblePhoneNumber(value: string): boolean

Checks if the value could be a "possible" phone number. In other words, it checks if the phone number length is correct. The actual phone number digits themselves aren't validated.

import { isPossiblePhoneNumber } from 'react-phone-number-input'
isPossiblePhoneNumber('+12223333333') === true
isPossiblePhoneNumber('+1222333333') === false

isValidPhoneNumber(value: string): boolean

Checks if the value represents a "valid" phone number. In other words, it checks if the phone number length is correct, and all digits are correct too.

import { isValidPhoneNumber } from 'react-phone-number-input'
isValidPhoneNumber('+12223333333') === false
isValidPhoneNumber('+12133734253') === true

By default this component uses min "metadata" which results in less strict validation compared to max or mobile.

How to choose between isPossiblePhoneNumber() and isValidPhoneNumber(): I'd personally prefer isPossiblePhoneNumber() because its strength is in its weakness. isValidPhoneNumber() is a double-edged sword in terms of how strict it is, and when not kept up-to-date, it could get stale over time and start rejecting freshly-assigned phone number ranges.

parsePhoneNumber(input: string): PhoneNumber?

Parses a PhoneNumber object from a string. This is simply an alias for parsePhoneNumber() from libphonenumber-js. Can be used to get country from value.

import { parsePhoneNumber } from 'react-phone-number-input'
const phoneNumber = parsePhoneNumber('+12133734253')
if (phoneNumber) {
  phoneNumber.country === 'US'
} else {
  // The argument is not a valid phone number
}

getCountryCallingCode(country: string): string

Returns the "country calling code" of a country. The country argument must be a supported country code.

This is simply an alias for getCountryCallingCode() from libphonenumber-js.

import { getCountryCallingCode } from 'react-phone-number-input'
getCountryCallingCode('US') === '1'

isSupportedCountry(country: string): boolean

Checks if a given country code is supported by this library.

This is simply an alias for isSupportedCountry() from libphonenumber-js.

import { isSupportedCountry } from 'react-phone-number-input'
isSupportedCountry('US') === true

Flags URL

By default, all flags are linked from country-flag-icons's GitHub pages website as <img src="..."/>s. Any other flag icons could be used instead by passing a custom flagUrl property (which is "https://purecatamphetamine.github.io/country-flag-icons/3x2/{XX}.svg" by default) and specifying their aspect ratio via --PhoneInputCountryFlag-aspectRatio CSS variable (which is 1.5 by default, meaning "3x2" aspect ratio).

For example, using custom "4x3" flag icons would be as simple as:

:root {
  --PhoneInputCountryFlag-aspectRatio: 1.333;
}

<PhoneInput flagUrl="https://example.com/flags/4x3/{xx}.svg" .../>

Including all flags

Linking flag icons as external <img/>s is only done to reduce the overall bundle size, because including all country flags in the code as inline <svg/>s would increase the bundle size by 44 kB (after gzip).

If bundle size is not an issue (for example, for a standalone non-web application, or an "intranet" application), then all country flags can be included directly in the code by passing the flags property:

import PhoneInput from 'react-phone-number-input'
import flags from 'react-phone-number-input/flags'

<PhoneInput flags={flags} .../>

Localization

Language translation can be applied by passing a custom labels property value. This component comes pre-packaged with several importable translations.

import russianLabels from 'react-phone-number-input/locale/ru'

<PhoneInput labels={russianLabels} .../>

If labels for a certain language are missing, one could submit a pull request to add those.

Where could one get the list of country names for a given language.

There's a myriad sources on the internet. Modern web browsers even have an official built-in list of country names in all languages.

For example, one could copy country names from github.com/umpirsky/country-list.

import countryNamesInRussian from 'country-list/data/ru/country.json'

// Outputs a JSON with the country names.
JSON.stringify(
  Object.keys(countryNamesInRussian).sort()
    .reduce((all, country) => ({
      ...all,
      [country]: countries[country]
    }), {}),
  null,
  '\t'
)

Note that this library uses the term "country code" rather broadly, including both the official and ISO-3166-1 country codes and a few of unofficial "country codes", so a translation should include the labels for both official and unofficial "country codes".

Also, a translation should include the following miscellaneous labels:

• country — is used as an aria-label for the country <select/> dropdown. It could also be used as a label for a hypothetical country name autocomplete input field.
• ZZ — is used when no country is selected.
• phone — could hypothetically be used as a label for the phone number input field.
• ext — could hypothetically be used as a label for a phone number extension input field.

The final format for a translation file is:

{
  "country": "Phone number country",
  "phone": "Phone",
  "ext": "ext.",
  // The rest are country names, including "unofficial" ones
  // like `AC`, `TA`, `XK`, and `ZZ` for "International".
  ...,
  "RO": "Romania",
  "RS": "Serbia",
  "RU": "Russia",
  ...,
  "ZZ": "International"
}

min vs max vs mobile

This component uses libphonenumber-js which lets a developer choose from different "metadata" sets, where a "metadata" set is a complete list of phone number parsing and formatting rules for all possible countries.

As one may guess, the complete list of those rules is huge, so this package provides a way to optimize the bundle size by choosing between max, min, mobile or "custom" metadata, depending on the project's needs.

• min — (default) The smallest metadata set

  • Is about 80 kilobytes in size (libphonenumber-js/metadata.min.json file)
  • Choose this when:
    • You don't need to detect phone number type — "fixed line", "mobile", etc — via libphonenumber-js functions
    • You're fine with just validating phone number length via isPossiblePhoneNumber() and you don't need to strictly validate phone number digits via isValidPhoneNumber()

• max — The complete metadata set

  • Is about 145 kilobytes in size (libphonenumber-js/metadata.max.json file)
  • Choose this when:
    • The basic isPossiblePhoneNumber() phone number length check is not enough for you and you need the strict phone number digits validation via isValidPhoneNumber()
    • You need to detect phone number type — "fixed line", "mobile", etc — via libphonenumber-js functions

• mobile — The complete metadata set for dealing with mobile numbers only

  • Is about 95 kilobytes in size (libphonenumber-js/metadata.mobile.json file)
  • Choose this when:
    • You need max metadata capabilities and you only accept mobile numbers
      • It will still be able to handle non-mobile numbers just fine, with the only difference that isValidPhoneNumber() or isPossiblePhoneNumber() might potentially return false for them, or it could be unable to determine the phone number type.

• "custom" — (advanced) Create your own metadata that is even smaller in size by dropping support for most countries

  • The size depends on the number of supported countries and the type of supported phone numbers
  • Choose this when:
    • You only need to support a handful of countries and you're absolutely obsessed with reducing the bundle size

Choose one from the above and then simply import the components or functions from the relevant sub-package.

For "with country select" component, the import paths are:

• min — react-phone-number-input
• max — react-phone-number-input/max
• mobile — react-phone-number-input/mobile
• "custom" — react-phone-number-input/core

For "without country select" component, the import paths are:

• min — react-phone-number-input/input
• max — react-phone-number-input/input-max
• mobile — react-phone-number-input/input-mobile
• "custom" — react-phone-number-input/input-core

As for "custom" metadata, it could be used in those rare cases when not all countries are needed and a developer would really prefer to reduce the bundle size to a minimum. In that case, one could generate their own "custom" metadata set and then import the functions from react-phone-number-input/core or react-phone-number-input/input-core sub-package which doesn't come pre-packaged with any metadata and instead requires metadata property be passed.

Bug reporting

If you think that the phone number parsing/formatting/validation engine malfunctions for a particular phone number then it could be for several reasons:

• libphonenumber-js, which is what this package uses internally, parses/formats/validates phone numbers incorrectly. To test if that's the case, follow the instructions outlined in the bug reporting section of libphonenumber-js readme.

• react-phone-number-input's exported isValidPhoneNumber() function is a "stripped-down" "min" version of the same function exported from libphonenumber-js package, so if you think that the validation is too lax, use the isValidPhoneNumber() function from libphonenumber-js/max package instead.

• In other cases, report issues in this repo.

Autocomplete

There's a feature of a web browser when it automatically populates the input with the user's own phone number. It's called "autocomplete".

To enable this feature, make sure you're putting <PhoneInput/> component inside a <form/>, otherwise this feature may not be working: the user will be tapping on their phone number "suggestion" but nothing would be happening.

react-hook-form

To use this component with react-hook-form, use one of the four exported components:

// "Without country select" component.
import PhoneInput from 'react-phone-number-input/react-hook-form-input'

// "Without country select" component (to pass custom `metadata` property).
import PhoneInput from 'react-phone-number-input/react-hook-form-input-core'

// "With country select" component.
import PhoneInputWithCountry from 'react-phone-number-input/react-hook-form'

// "With country select" component (to pass custom `metadata` property).
import PhoneInputWithCountry from 'react-phone-number-input/react-hook-form-core'

Example:

// "Without country select" component.
import PhoneInput from "react-phone-number-input/react-hook-form-input"

// "With country select" component.
import PhoneInputWithCountry from "react-phone-number-input/react-hook-form"

import { useForm } from "react-hook-form"

export default function Form() {
  const {
    // Either pass a `control` property to the component
    // or wrap it in a `<FormProvider/>`.
    control,
    handleSubmit
  } = useForm()

  return (
    <form onSubmit={handleSubmit(...)}>
      <PhoneInput
        name="phoneInput"
        control={control}
        rules={{ required: true }} />

      <PhoneInputWithCountry
        name="phoneInputWithCountrySelect"
        control={control}
        rules={{ required: true }} />

      <button type="submit">
        Submit
      </button>
    </form>
  )
}

Both components accept properties:

• name — (required) Form field name.

• control — (required) The control object returned from useForm().

• rules — (optional) Validation rules in the same format as for register(). Example: {{ required: true, validate: isPossiblePhoneNumber }}.

• defaultValue — (optional) A default value could be passed directly to the component, or as part of the defaultValues parameter of useForm().

Customization

"With country select" <PhoneInput/> component accepts some customization properties:

• metadata — Custom libphonenumber-js "metadata". Could be used to supply "metadata" that only contains a small subset of countries.

• labels — Custom translation "messages": country names, miscellanous labels. Example for English: react-phone-number-input/locale/en.json

• inputComponent — Custom phone number <input/> component.

• countrySelectComponent — Custom country <select/> component.

• internationalIcon — Custom "International" icon component.

• flagComponent — Custom flag icon component.

• countrySelectProps.arrowComponent — Custom "arrow" component of the default country <select/>. Renders an "arrow" "dropdown" icon. Doesn't receive any properties.

All those customization properties have their default values which are, therefore, always included in the application bundle, regardless of whether those default property values get overridden by any custom ones.

Those who'd like to exclude the default values just for metadata and labels properties could import the component from react-phone-number-input/core subpackage rather than from react-phone-number-input package.

countrySelectComponent

React component for the country select. See CountrySelect.js for an example.

Receives properties:

• name: string? — HTML name attribute.
• value: string? — The currently selected country code (undefined in case of "International").
• onChange(value: string?) — Updates the value (to undefined in case of "International").
• onFocus() — Is used to toggle the --focus CSS class.
• onBlur() — Is used to toggle the --focus CSS class.
• options: object[] — The list of all selectable countries (including "International") each being an object of shape { value: string?, label: string }.
• iconComponent: PropTypes.elementType — React component that renders a country icon: <Icon country={value}/>. If country is undefined then it renders an "International" icon.
• disabled: boolean? — HTML disabled attribute.
• readOnly: boolean? — HTML readonly attribute.
• tabIndex: (number|string)? — HTML tabIndex attribute.
• className: string — CSS class name.

inputComponent

A React component for the phone number input field. Is "input" by default, meaning that it renders a standard DOM <input/>.

Any custom input component implementation must use React.forwardRef() to "forward" ref to the underlying "core" <input/> component.

Receives properties:

• value: string — The formatted value.
• onChange(event: Event) — Updates the formatted value from event.target.value.
• onFocus() — Is used to toggle the --focus CSS class.
• onBlur(event: Event) — Is used to toggle the --focus CSS class.
• Other properties like type="tel" or autoComplete="tel" that should be passed through to the DOM <input/>.

flagComponent

Renders a country flag icon.

Receives properties:

• country: string — A two-letter ISO country code. Example: "RU".
• countryName: string — Country name. Example: "Russia".
• flags?: object — An object that contains a flag icon component for each country. Same as the flags property of the react-phone-number-input component.
• flagUrl?: string — A template for a country flag icon image URL. Same as the flagUrl property of the react-phone-number-input component.
• className: string — CSS class name.

internationalIcon

Renders an "International" icon. For example, the default one is a globe icon. The icon is shown instead of a country flag when the phone number is in international format (i.e. starts with a + character) but is either incomplete or doesn't belong to any known country.

Receives properties:

• title: string — ARIA label.
• aspectRatio: number — Icon aspect ratio: width / height.
• className: string — CSS class name.

CDN

To include this library directly via a <script/> tag on a page, one can use any npm CDN service, e.g. unpkg.com or jsdelivr.com

<!-- Default ("min" metadata). -->
<script src="https://unpkg.com/react-phone-number-input@3.x/bundle/react-phone-number-input.js"></script>

<!-- Or "max" metadata. -->
<script src="https://unpkg.com/react-phone-number-input@3.x/bundle/react-phone-number-input-max.js"></script>

<!-- Or "mobile" metadata. -->
<script src="https://unpkg.com/react-phone-number-input@3.x/bundle/react-phone-number-input-mobile.js"></script>

<!-- Styles for the component. -->
<!-- Internet Explorer requires transpiling CSS variables. -->
<link rel="stylesheet" href="https://unpkg.com/react-phone-number-input@3.x/bundle/style.css"/>

<script>
  var PhoneInput = window.PhoneInput.default
</script>

Without country select:

<!-- Without country `<select/>` ("min" metadata). -->
<script src="https://unpkg.com/react-phone-number-input@3.x/bundle/react-phone-number-input-input.js"></script>

<script>
  var PhoneInput = window.PhoneInput.default
</script>

Country code

A "country code" is a two-letter ISO country code like "US", "CA", etc.

However, this library uses libphonenumber-js's variant of the "country code" term, which is rather broad and includes both the official ISO country codes and a few of unofficial "country codes". For that reason, a developer should use a "country code" returned from this library with caution in an application that only expects the official ISO "country codes" to exist. For example, such application will likely not have a label or a flag for such an unofficial "country code". In that case, a developer could manually transform an unofficial "country code" returned from this library to an official ISO country code of the most suitable "parent" country.

To check whether a certain two-letter "country code" is supported by this library, use isSupportedCountry() function.

Tests

This component comes with 100% code coverage for the core ./source/helpers directory.

To run tests:

npm test

To generate a code coverage report:

npm run test-coverage

The code coverage report can be viewed by opening ./coverage/lcov-report/index.html.

If the code coverage report is "empty" then it means that a newer version of handlebars was accidentally installed and should be reverted to handlebars@4.5.3.

The handlebars@4.5.3 workaround in devDependencies is for the test coverage to not produce empty reports:

Handlebars: Access has been denied to resolve the property "statements" because it is not an "own property" of its parent.
You can add a runtime option to disable the check or this warning:
See https://handlebarsjs.com/api-reference/runtime-options.html#options-to-control-prototype-access for details

GitHub

On March 9th, 2020, GitHub, Inc. silently banned my account (erasing all my repos, issues and comments) without any notice or explanation. Because of that, all source codes had to be promptly moved to GitLab. GitHub repo is now deprecated, and the latest source codes can be found on GitLab, which is also the place to report any issues.

License

MIT