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Upgrade Guide (v1 -> v2)

Use React 0.14 or 15

React Intl v2 has a peer dependency on react@^0.14.0 || ^15.0.0-0 and now takes advantage of features and changes in React 0.14 and also works with React 15.

Update How Locale Data is Added

The locale data modules in React Intl v2 have been refactored to provide data, instead of mutating React Intl's internal locale data registry. The react-intl/locale-data/* files are also decoupled from the ReactIntl global and instead provide UMD modules with a new ReactIntlLocaleData global. These changes, mean apps need update how they are registering the locale data they need in the browser.

Add Call to addLocaleData() in Browser

There is now an addLocaleData() function that needs to be called with the locale data that has been loaded. You can do the following in your main client JavaScript entry point:

This assumes a locale data <script> is added based on the request; e.g., for French speaking users:

<script src="react-intl/locale-data/fr.js"></script>

Using <script src="react-intl/dist/react-intl.js>:

if ('ReactIntl' in window && 'ReactIntlLocaleData' in window) {
Object.keys(ReactIntlLocaleData).forEach(lang => {

Using Browserify/Webpack to Load React Intl:

import {addLocaleData} from 'react-intl'

if ('ReactIntlLocaleData' in window) {
Object.keys(ReactIntlLocaleData).forEach(lang => {

This decoupling of the library from the locale data, allows for the files to be loaded via <script async>. When using async scripts, your client bootstrapping code will need to wait for the load event, including the code above. :::

Remove Intl Mixin

The IntlMixin has been removed from React Intl v2. The mixin did two things: it automatically propagated locales, formats, and messages throughout an app's hierarchy, and it provided an imperative API via format*() functions. These jobs are now handled by <IntlProvider> and injectIntl(), respectively:

Update to IntlProvider

In React Intl v1, you would add the IntlMixin to your root component; e.g., <App>. Remove the IntlMixin and instead wrap your root component with <IntlProvider>:

import ReactDOM from 'react-dom'
import {IntlProvider} from 'react-intl'

<IntlProvider locale="en">
<App />

The locale prop is singular, required, and only accepts a string value. This is a simplification of the plural locales prop used by the IntlMixin.

Update to injectIntl()

The IntlMixin also provided the imperative API for custom components to use the format*() methods; e.g., formatDate() to get formatted strings for using in places like title and aria attribute. Remove the IntlMixin and instead use the injectIntl() Hight Order Component (HOC) factory function to inject the imperative API via props.

Here's an example of a custom <RelativeTime> stateless component which uses injectIntl() and the imperative formatDate() API:

import React from 'react'
import {injectIntl, FormattedRelative} from 'react-intl'

const to2Digits = num => `${num < 10 ? `0${num}` : num}`

const RelativeTime = ({date, intl}) => {
date = new Date(date)

let year = date.getFullYear()
let month = date.getMonth() + 1
let day = date.getDate()

let formattedDate = intl.formatDate(date, {
year: 'long',
month: 'numeric',
day: 'numeric',

return (
<FormattedRelative value={date} />

export default injectIntl(RelativeTime)

injectIntl() is similar to a connect() HOC factory function you might find in a Flux framework to connect a component to a store.

Change How Messages are Formatted

The way string messages are formatted in React Intl v2 has changed significantly! This is the most disruptive set of change when upgrading from v1 to v2; but it enables many great new features.

React Intl v2 introduces a new Message Descriptor concept which can be used to define an app's default string messages. A Message Descriptor is an object with the following properties, id is the only required prop:

  • id: A unique, stable identifier for the message
  • description: Context for the translator about how it's used in the UI
  • defaultMessage: The default message (probably in English)

This upgrade guide will focus on using Message Descriptors that only contain an id property.

Flatten messages Object

React Intl v2 no longer supports nested messages objects, instead the collection of translated string messages passed to <IntlProvider> must be flat. This is an explicit design choice which simplifies while increasing flexibility. React Intl v2 does not apply any special semantics to strings with dots; e.g., "namespaced.string_id".

Apps using a nested messages object structure could use the following function to flatten their object according to React Intl v1's semantics:

function flattenMessages(nestedMessages, prefix = '') {
return Object.keys(nestedMessages).reduce((messages, key) => {
let value = nestedMessages[key]
let prefixedKey = prefix ? `${prefix}.${key}` : key

if (typeof value === 'string') {
messages[prefixedKey] = value
} else {
Object.assign(messages, flattenMessages(value, prefixedKey))

return messages
}, {})

let messages = flattenMessages(nestedMessages)

Message ids can still contain "."s, so the ids themselves remain the same, it's only the messages object structure that needs to change.

Replace getIntlMessage() Calls with Message Descriptors

The getIntlMessage() method that was provided by the IntlMixin has been removed in React Intl v2. It was simply a helper that interpreted a message id string with "."s by looking up the translated message in a nested messages object. With the removal of IntlMixin and the change to a flat messages object, this method has been removed.

All calls to getIntlMessage() need to be replaced with a Message Descriptor.




id: ''

Update formatMessage() Calls

A typical pattern when calling formatMessage() is to nest a call to getIntlMessage(). These can be easily updated:


let message = this.formatMessage(this.getIntlMessage(''), values)


let message = this.props.intl.formatMessage({id: ''}, values)

In React Intl v2, the formatMessage() function is injected via injectIntl().

Update FormattedMessage and FormattedHTMLMessage Instances

The props for these two components have completely changed in React Intl v2. Instead of taking a message prop and treating all other props as values to fill in placeholders in a message, <FormattedMessage> and <FormattedHTMLMessage> now the same props as a Message Descriptor plus a new values prop.

The new values prop groups all of the message's placeholder values together into an object.

The following example shows up to update a <FormattedMessage> instance to use the new props and remove the call to getIntlMessage():


<FormattedMessage message={this.getIntlMessage('greeting')} name="Eric" />


<FormattedMessage id="greeting" values={{name: 'Eric'}} />

Update How Relative Times are Formatted

Minor changes have been made to how the "now" reference time is specified when formatting relative times in React Intl v2. It's uncommon to specify this value outside of test code, so it might not exist in your app.

Rename FormattedRelative's now Prop to initialNow

A new feature has been added to <FormattedRelative> instances in React Intl v2, they now "tick" and stay up to date. Since time moves forward, it was confusing to have a prop named now, so it has been renamed to initialNow. Any <FormattedRelative> instances that use now should update to prop name to initialNow:


<FormattedRelative value={date} now={otherDate} />


<FormattedRelative value={date} initialNow={otherDate} />

The <IntlProvider> component also has a initialNow prop which can be assigned a value to stabilize the "now" reference time for all <FormattedRelative> instances. This is useful for universal/isomorphic apps to proper React checksums between the server and client initial render.

Merge formatRelative()'s Second and Third Arguments

The signature of the formatRelative() function has been aligned with the other format*() functions and in React Intl v2, it only accepts two arguments: value and options. To specify a "now" reference time, add it to the options argument, and remove the third formatOptions argument:


let relative = this.formatRelative(date, {units: 'hour'}, {now: otherDate})


let relative = this.props.intl.formatRelative(date, {
units: 'hour',
now: otherDate,

In React Intl v2, the formatRelative() function is injected via injectIntl().