Refactor i18n/intl utils, support icu only, remove renderText

build/intl-linter/linter.ts

@@ -14,6 +14,7 @@ import { deepEqual } from 'assert';
 import type { Rule } from './utils/rule';
 
 import icuPrefix from './rules/icuPrefix';
+import wrapEmoji from './rules/wrapEmoji';
 import onePlural from './rules/onePlural';
 import noLegacyVariables from './rules/noLegacyVariables';
 import noNestedChoice from './rules/noNestedChoice';
@@ -24,6 +25,7 @@ import pluralPound from './rules/pluralPound';
 
 const RULES = [
   icuPrefix,
+  wrapEmoji,
   noLegacyVariables,
   noNestedChoice,
   noOffset,
@@ -74,6 +76,26 @@ const tests: Record<string, Test> = {
     messageformat: '$a$',
     expectErrors: ['noLegacyVariables'],
   },
+  'icu:wrapEmoji:1': {
+    messageformat: '👩',
+    expectErrors: ['wrapEmoji'],
+  },
+  'icu:wrapEmoji:2': {
+    messageformat: '<emoji>👩 extra</emoji>',
+    expectErrors: ['wrapEmoji'],
+  },
+  'icu:wrapEmoji:3': {
+    messageformat: '<emoji>👩👩</emoji>',
+    expectErrors: ['wrapEmoji'],
+  },
+  'icu:wrapEmoji:4': {
+    messageformat: '<emoji>{emoji}</emoji>',
+    expectErrors: ['wrapEmoji'],
+  },
+  'icu:wrapEmoji:5': {
+    messageformat: '<emoji>👩</emoji>',
+    expectErrors: [],
+  },
 };
 
 type Report = {

build/intl-linter/rules/wrapEmoji.ts

@@ -0,0 +1,73 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import getEmojiRegex from 'emoji-regex';
+import type {
+  MessageFormatElement,
+  TagElement,
+} from '@formatjs/icu-messageformat-parser';
+import {
+  isTagElement,
+  isLiteralElement,
+} from '@formatjs/icu-messageformat-parser';
+import { rule } from '../utils/rule';
+
+function isEmojiTag(
+  element: MessageFormatElement | null
+): element is TagElement {
+  return element != null && isTagElement(element) && element.value === 'emoji';
+}
+
+export default rule('wrapEmoji', context => {
+  const emojiRegex = getEmojiRegex();
+  return {
+    enterTag(element) {
+      if (!isEmojiTag(element)) {
+        return;
+      }
+
+      if (element.children.length !== 1) {
+        // multiple children
+        context.report(
+          'Only use a single literal emoji in <emoji> tags with no additional text.',
+          element.location
+        );
+        return;
+      }
+
+      const child = element.children[0];
+      if (!isLiteralElement(child)) {
+        // non-literal
+        context.report(
+          'Only use a single literal emoji in <emoji> tags with no additional text.',
+          child.location
+        );
+      }
+    },
+    enterLiteral(element, parent) {
+      const match = element.value.match(emojiRegex);
+      if (match == null) {
+        // no emoji
+        return;
+      }
+
+      if (!isEmojiTag(parent)) {
+        // unwrapped
+        context.report(
+          'Use <emoji> to wrap emoji in translation strings.',
+          element.location
+        );
+        return;
+      }
+
+      const emoji = match[0];
+      if (emoji !== element.value) {
+        // extra text other than emoji
+        context.report(
+          'Only use a single literal emoji in <emoji> tags with no additional text.',
+          element.location
+        );
+      }
+    },
+  };
+});

package.json

@@ -277,12 +277,14 @@
     "eslint-plugin-mocha": "10.1.0",
     "eslint-plugin-more": "1.0.5",
     "eslint-plugin-react": "7.31.10",
+    "execa": "5.1.1",
     "html-webpack-plugin": "5.3.1",
     "json-to-ast": "2.1.0",
     "mocha": "9.1.3",
     "node-gyp": "9.0.0",
     "npm-run-all": "4.1.5",
     "nyc": "11.4.1",
+    "p-limit": "3.1.0",
     "patch-package": "6.4.7",
     "playwright": "1.33.0",
     "prettier": "2.8.0",

ts/components/Intl.stories.tsx

@@ -20,7 +20,6 @@ const createProps = (overrideProps: Partial<Props> = {}): Props => ({
   i18n,
   id: overrideProps.id || '',
   components: overrideProps.components,
-  renderText: overrideProps.renderText,
 });
 
 // eslint-disable-next-line max-len
@@ -29,18 +28,18 @@ const Template: Story<Props> = args => <Intl {...args} />;
 
 export const NoReplacements = Template.bind({});
 NoReplacements.args = createProps({
-  id: 'deleteAndRestart',
+  id: 'icu:deleteAndRestart',
 });
 
 export const SingleStringReplacement = Template.bind({});
 SingleStringReplacement.args = createProps({
-  id: 'leftTheGroup',
+  id: 'icu:leftTheGroup',
   components: { name: 'Theodora' },
 });
 
 export const SingleTagReplacement = Template.bind({});
 SingleTagReplacement.args = createProps({
-  id: 'leftTheGroup',
+  id: 'icu:leftTheGroup',
   components: {
     name: (
       <button type="button" key="a-button">
@@ -52,7 +51,7 @@ SingleTagReplacement.args = createProps({
 
 export const MultipleStringReplacement = Template.bind({});
 MultipleStringReplacement.args = createProps({
-  id: 'changedRightAfterVerify',
+  id: 'icu:changedRightAfterVerify',
   components: {
     name1: 'Fred',
     name2: 'The Fredster',
@@ -61,19 +60,22 @@ MultipleStringReplacement.args = createProps({
 
 export const MultipleTagReplacement = Template.bind({});
 MultipleTagReplacement.args = createProps({
-  id: 'changedRightAfterVerify',
+  id: 'icu:changedRightAfterVerify',
   components: {
     name1: <b>Fred</b>,
     name2: <b>The Fredster</b>,
   },
 });
 
-export const CustomRender = Template.bind({});
+export function Emoji(): JSX.Element {
-CustomRender.args = createProps({
+  const customI18n = setupI18n('en', {
-  id: 'deleteAndRestart',
+    'icu:emoji': {
-  renderText: ({ text: theText, key }) => (
+      messageformat: '<emoji>👋</emoji> Hello, world!',
-    <div style={{ backgroundColor: 'purple', color: 'orange' }} key={key}>
+    },
-      {theText}
+  });
-    </div>
+
-  ),
+  return (
-});
+    // eslint-disable-next-line local-rules/valid-i18n-keys
+    <Intl i18n={customI18n} id="icu:emoji" />
+  );
+}

ts/components/Intl.tsx

@@ -5,7 +5,7 @@ import React from 'react';
 import type { ReactNode } from 'react';
 
 import type { FormatXMLElementFn } from 'intl-messageformat';
-import type { LocalizerType, RenderTextCallbackType } from '../types/Util';
+import type { LocalizerType } from '../types/Util';
 import type { ReplacementValuesType } from '../types/I18N';
 import * as log from '../logging/log';
 import { strictAssert } from '../util/assert';
@@ -23,118 +23,29 @@ export type Props = {
   id: string;
   i18n: LocalizerType;
   components?: IntlComponentsType;
-  renderText?: RenderTextCallbackType;
 };
 
-const defaultRenderText: RenderTextCallbackType = ({ text, key }) => (
+export function Intl({
-  <React.Fragment key={key}>{text}</React.Fragment>
-);
-
-export class Intl extends React.Component<Props> {
-  public getComponent(
-    index: number,
-    placeholderName: string,
-    key: number
-  ): JSX.Element | null {
-    const { id, components } = this.props;
-
-    if (!components) {
-      log.error(
-        `Error: Intl component prop not provided; Metadata: id '${id}', index ${index}, placeholder '${placeholderName}'`
-      );
-      return null;
-    }
-
-    if (Array.isArray(components)) {
-      if (!components || !components.length || components.length <= index) {
-        log.error(
-          `Error: Intl missing provided component for id '${id}', index ${index}`
-        );
-
-        return null;
-      }
-
-      return <React.Fragment key={key}>{components[index]}</React.Fragment>;
-    }
-
-    const value = components[placeholderName];
-    if (!value) {
-      log.error(
-        `Error: Intl missing provided component for id '${id}', placeholder '${placeholderName}'`
-      );
-
-      return null;
-    }
-
-    return <React.Fragment key={key}>{value}</React.Fragment>;
-  }
-
-  // eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
-  public override render() {
-    const {
   components,
   id,
   // Indirection for linter/migration tooling
   i18n: localizer,
-      renderText = defaultRenderText,
+}: Props): JSX.Element | null {
-    } = this.props;
-
   if (!id) {
     log.error('Error: Intl id prop not provided');
     return null;
   }
 
-    if (!localizer.isLegacyFormat(id)) {
+  strictAssert(
+    !localizer.isLegacyFormat(id),
+    `Legacy message format is no longer supported ${id}`
+  );
+
   strictAssert(
     !Array.isArray(components),
     `components cannot be an array for ICU message ${id}`
   );
+
   const intl = localizer.getIntl();
-      return intl.formatMessage({ id }, components);
+  return <>{intl.formatMessage({ id }, components, {})}</>;
-    }
-
-    const text = localizer(id);
-    const results: Array<
-      string | JSX.Element | Array<string | JSX.Element> | null
-    > = [];
-    const FIND_REPLACEMENTS = /\$([^$]+)\$/g;
-
-    if (Array.isArray(components) && components.length > 1) {
-      throw new Error(
-        'Array syntax is not supported with more than one placeholder'
-      );
-    }
-
-    let componentIndex = 0;
-    let key = 0;
-    let lastTextIndex = 0;
-    let match = FIND_REPLACEMENTS.exec(text);
-
-    if (!match) {
-      return renderText({ text, key: 0 });
-    }
-
-    while (match) {
-      if (lastTextIndex < match.index) {
-        const textWithNoReplacements = text.slice(lastTextIndex, match.index);
-        results.push(renderText({ text: textWithNoReplacements, key }));
-        key += 1;
-      }
-
-      const placeholderName = match[1];
-      results.push(this.getComponent(componentIndex, placeholderName, key));
-      componentIndex += 1;
-      key += 1;
-
-      lastTextIndex = FIND_REPLACEMENTS.lastIndex;
-      match = FIND_REPLACEMENTS.exec(text);
-    }
-
-    if (lastTextIndex < text.length) {
-      results.push(renderText({ text: text.slice(lastTextIndex), key }));
-      key += 1;
-    }
-
-    return results;
-  }
 }

ts/components/WhatsNewModal.tsx

@@ -7,8 +7,7 @@ import moment from 'moment';
 
 import { Modal } from './Modal';
 import { Intl } from './Intl';
-import { Emojify } from './conversation/Emojify';
+import type { LocalizerType } from '../types/Util';
-import type { LocalizerType, RenderTextCallbackType } from '../types/Util';
 
 export type PropsType = {
   hideWhatsNewModal: () => unknown;
@@ -21,10 +20,6 @@ type ReleaseNotesType = {
   features: Array<JSX.Element>;
 };
 
-const renderText: RenderTextCallbackType = ({ key, text }) => (
-  <Emojify key={key} text={text} />
-);
-
 export function WhatsNewModal({
   i18n,
   hideWhatsNewModal,
@@ -35,11 +30,10 @@ export function WhatsNewModal({
     date: new Date(window.getBuildCreation?.() || Date.now()),
     version: window.getVersion?.(),
     features: [
-      <Intl i18n={i18n} id="icu:WhatsNew__v6.21--0" renderText={renderText} />,
+      <Intl i18n={i18n} id="icu:WhatsNew__v6.21--0" />,
       <Intl
         i18n={i18n}
         id="icu:WhatsNew__v6.21--1"
-        renderText={renderText}
         components={{
           complexspaces: (
             <a href="https://github.com/complexspaces">@complexspaces</a>

ts/scripts/remove-strings.ts

@@ -1,66 +1,104 @@
 // Copyright 2023 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
-import fs from 'fs';
+import chalk from 'chalk';
+import execa from 'execa';
+import fs from 'fs/promises';
+import pLimit from 'p-limit';
 import path from 'path';
-import { spawnSync } from 'child_process';
-import type { StdioOptions } from 'child_process';
 
 import { MONTH } from '../util/durations';
 import { isOlderThan } from '../util/timestamp';
 
 const ROOT_DIR = path.join(__dirname, '..', '..');
 const MESSAGES_FILE = path.join(ROOT_DIR, '_locales', 'en', 'messages.json');
-const SPAWN_OPTS = {
-  cwd: ROOT_DIR,
-  stdio: [null, 'pipe', 'inherit'] as StdioOptions,
-};
 
-const messages = JSON.parse(fs.readFileSync(MESSAGES_FILE).toString());
+const limitter = pLimit(10);
 
-const stillUsed = new Set<string>();
+async function main() {
+  const messages = JSON.parse(await fs.readFile(MESSAGES_FILE, 'utf-8'));
+
+  const stillUsed = new Set<string>();
+
+  await Promise.all(
+    Object.keys(messages).map(key =>
+      limitter(async () => {
+        const value = messages[key];
 
-for (const [key, value] of Object.entries(messages)) {
         const match = (value as Record<string, string>).description?.match(
-    /\(\s*deleted\s+(\d{4}\/\d{2}\/\d{2})\s*\)/
+          /\(\s*deleted\s+(\d{2,4}\/\d{2}\/\d{2,4})\s*\)/
         );
         if (!match) {
-    continue;
+          return;
         }
 
         const deletedAt = new Date(match[1]).getTime();
         if (!isOlderThan(deletedAt, MONTH)) {
-    continue;
+          return;
         }
 
         // Find uses in either:
         // - `i18n('key')`
         // - `<Intl id="key"/>`
-  const { status, stdout } = spawnSync(
+
+        try {
+          const result = await execa(
             'git',
-    ['grep', '--extended-regexp', `'${key}'|id="${key}"`],
+            // prettier-ignore
-    SPAWN_OPTS
+            [
+              'grep',
+              '--extended-regexp',
+              `'${key}'|id="${key}"`,
+              '--',
+              '**',
+              ':!\\_locales/**',
+              ':!\\sticker-creator/**',
+            ],
+            {
+              cwd: ROOT_DIR,
+              stdin: 'ignore',
+              stdout: 'pipe',
+              stderr: 'inherit',
+            }
           );
 
           // Match found
-  if (status === 0) {
           console.error(
+            chalk.red(
               `ERROR: String is still used: "${key}", deleted on ${match[1]}`
+            )
           );
-    console.error(stdout.toString().trim());
+          console.error(result.stdout.trim());
           console.error('');
           stillUsed.add(key);
-  } else {
+        } catch (error) {
-    console.log(`Removing string: "${key}", deleted on ${match[1]}`);
+          if (error.exitCode === 1) {
+            console.log(
+              chalk.dim(`Removing string: "${key}", deleted on ${match[1]}`)
+            );
             delete messages[key];
+          } else {
+            throw error;
           }
-}
+        }
+      })
+    )
+  );
 
-if (stillUsed.size !== 0) {
+  if (stillUsed.size !== 0) {
     console.error(
-    `ERROR: Didn't remove ${[...stillUsed]} strings because of errors above`
+      `ERROR: Didn't remove ${stillUsed.size} strings because of errors above`,
+      Array.from(stillUsed)
+        .map(str => `- ${str}`)
+        .join('\n')
     );
     console.error('ERROR: Not saving changes');
     process.exit(1);
+  }
+  await fs.writeFile(MESSAGES_FILE, `${JSON.stringify(messages, null, 2)}\n`);
 }
-fs.writeFileSync(MESSAGES_FILE, `${JSON.stringify(messages, null, 2)}\n`);
+
+main().catch(err => {
+  console.error(err);
+  process.exit(1);
+});

ts/test-both/types/setupI18n_test.ts

@@ -14,9 +14,18 @@ describe('setupI18n', () => {
   });
 
   describe('i18n', () => {
-    it('returns empty string for unknown string', () => {
+    it('throws an error for legacy strings', () => {
+      assert.throws(() => {
         // eslint-disable-next-line local-rules/valid-i18n-keys
-      assert.strictEqual(i18n('random'), '');
+        i18n('legacystring');
+      }, /Legacy message format is no longer supported/);
+    });
+
+    it('throws an error for unknown string', () => {
+      assert.throws(() => {
+        // eslint-disable-next-line local-rules/valid-i18n-keys
+        assert.strictEqual(i18n('icu:random'), '');
+      }, /missing translation/);
     });
     it('returns message for given string', () => {
       assert.strictEqual(i18n('icu:reportIssue'), 'Contact Support');

ts/types/I18N.ts

@@ -16,7 +16,6 @@ type SmartlingConfigType = {
 };
 
 export type LocaleMessageType = {
-  message?: string;
   messageformat?: string;
   description?: string;
 };

ts/util/setupI18n.ts

@@ -1,181 +0,0 @@
-// Copyright 2018 Signal Messenger, LLC
-// SPDX-License-Identifier: AGPL-3.0-only
-
-import memoize from '@formatjs/fast-memoize';
-import type { IntlShape } from 'react-intl';
-import { createIntl, createIntlCache } from 'react-intl';
-import type { LocaleMessageType, LocaleMessagesType } from '../types/I18N';
-import type { LocalizerType, ReplacementValuesType } from '../types/Util';
-import * as log from '../logging/log';
-import { strictAssert } from './assert';
-
-export const formatters = {
-  getNumberFormat: memoize((locale, opts) => {
-    return new Intl.NumberFormat(locale, opts);
-  }),
-  getDateTimeFormat: memoize((locale, opts) => {
-    return new Intl.DateTimeFormat(locale, opts);
-  }),
-  getPluralRules: memoize((locale, opts) => {
-    return new Intl.PluralRules(locale, opts);
-  }),
-};
-
-export function isLocaleMessageType(
-  value: unknown
-): value is LocaleMessageType {
-  return (
-    typeof value === 'object' &&
-    value != null &&
-    (Object.hasOwn(value, 'message') || Object.hasOwn(value, 'messageformat'))
-  );
-}
-
-export function classifyMessages(messages: LocaleMessagesType): {
-  icuMessages: Record<string, string>;
-  legacyMessages: Record<string, string>;
-} {
-  const icuMessages: Record<string, string> = {};
-  const legacyMessages: Record<string, string> = {};
-
-  for (const [key, value] of Object.entries(messages)) {
-    if (isLocaleMessageType(value)) {
-      if (value.messageformat != null) {
-        icuMessages[key] = value.messageformat;
-      } else if (value.message != null) {
-        legacyMessages[key] = value.message;
-      }
-    }
-  }
-
-  return { icuMessages, legacyMessages };
-}
-
-export function createCachedIntl(
-  locale: string,
-  icuMessages: Record<string, string>
-): IntlShape {
-  const intlCache = createIntlCache();
-  const intl = createIntl(
-    {
-      locale: locale.replace('_', '-'), // normalize supported locales to browser format
-      messages: icuMessages,
-    },
-    intlCache
-  );
-  return intl;
-}
-
-export function formatIcuMessage(
-  intl: IntlShape,
-  id: string,
-  substitutions: ReplacementValuesType | undefined
-): string {
-  strictAssert(
-    !Array.isArray(substitutions),
-    `substitutions must be an object for ICU message ${id}`
-  );
-  const result = intl.formatMessage({ id }, substitutions);
-  strictAssert(
-    typeof result === 'string',
-    'i18n: formatted translation result must be a string, must use <Intl/> component to render JSX'
-  );
-  return result;
-}
-
-export function setupI18n(
-  locale: string,
-  messages: LocaleMessagesType
-): LocalizerType {
-  if (!locale) {
-    throw new Error('i18n: locale parameter is required');
-  }
-  if (!messages) {
-    throw new Error('i18n: messages parameter is required');
-  }
-
-  const { icuMessages, legacyMessages } = classifyMessages(messages);
-  const intl = createCachedIntl(locale, icuMessages);
-
-  const getMessage: LocalizerType = (key, substitutions) => {
-    const messageformat = icuMessages[key];
-
-    if (messageformat != null) {
-      return formatIcuMessage(intl, key, substitutions);
-    }
-
-    const message = legacyMessages[key];
-    if (message == null) {
-      log.error(
-        `i18n: Attempted to get translation for nonexistent key '${key}'`
-      );
-      return '';
-    }
-
-    if (Array.isArray(substitutions) && substitutions.length > 1) {
-      throw new Error(
-        'Array syntax is not supported with more than one placeholder'
-      );
-    }
-    if (
-      typeof substitutions === 'string' ||
-      typeof substitutions === 'number'
-    ) {
-      throw new Error('You must provide either a map or an array');
-    }
-    if (!substitutions) {
-      return message;
-    }
-    if (Array.isArray(substitutions)) {
-      return substitutions.reduce(
-        (result, substitution) => result.replace(/\$.+?\$/, substitution),
-        message
-      );
-    }
-
-    const FIND_REPLACEMENTS = /\$([^$]+)\$/g;
-
-    let match = FIND_REPLACEMENTS.exec(message);
-    let builder = '';
-    let lastTextIndex = 0;
-
-    while (match) {
-      if (lastTextIndex < match.index) {
-        builder += message.slice(lastTextIndex, match.index);
-      }
-
-      const placeholderName = match[1];
-      let value = substitutions[placeholderName];
-      if (value == null) {
-        log.error(
-          `i18n: Value not provided for placeholder ${placeholderName} in key '${key}'`
-        );
-        value = '';
-      }
-      builder += value;
-
-      lastTextIndex = FIND_REPLACEMENTS.lastIndex;
-      match = FIND_REPLACEMENTS.exec(message);
-    }
-
-    if (lastTextIndex < message.length) {
-      builder += message.slice(lastTextIndex);
-    }
-
-    return builder;
-  };
-
-  getMessage.getIntl = () => {
-    return intl;
-  };
-  getMessage.isLegacyFormat = (key: string) => {
-    return legacyMessages[key] != null;
-  };
-  getMessage.getLocale = () => locale;
-  getMessage.getLocaleMessages = () => messages;
-  getMessage.getLocaleDirection = () => {
-    return window.getResolvedMessagesLocaleDirection();
-  };
-
-  return getMessage;
-}

ts/util/setupI18n.tsx

@@ -0,0 +1,110 @@
+// Copyright 2018 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import React from 'react';
+import type { IntlShape } from 'react-intl';
+import { createIntl, createIntlCache } from 'react-intl';
+import type { LocaleMessageType, LocaleMessagesType } from '../types/I18N';
+import type { LocalizerType } from '../types/Util';
+import { strictAssert } from './assert';
+import { Emojify } from '../components/conversation/Emojify';
+
+export function isLocaleMessageType(
+  value: unknown
+): value is LocaleMessageType {
+  return (
+    typeof value === 'object' &&
+    value != null &&
+    Object.hasOwn(value, 'messageformat')
+  );
+}
+
+function filterLegacyMessages(
+  messages: LocaleMessagesType
+): Record<string, string> {
+  const icuMessages: Record<string, string> = {};
+
+  for (const [key, value] of Object.entries(messages)) {
+    if (isLocaleMessageType(value) && value.messageformat != null) {
+      icuMessages[key] = value.messageformat;
+    }
+  }
+
+  return icuMessages;
+}
+
+export function renderEmoji(parts: ReadonlyArray<unknown>): JSX.Element {
+  strictAssert(parts.length === 1, '<emoji> must contain only one child');
+  const text = parts[0];
+  strictAssert(typeof text === 'string', '<emoji> must contain only text');
+  return <Emojify text={text} />;
+}
+
+export function createCachedIntl(
+  locale: string,
+  icuMessages: Record<string, string>
+): IntlShape {
+  const intlCache = createIntlCache();
+  const intl = createIntl(
+    {
+      locale: locale.replace('_', '-'), // normalize supported locales to browser format
+      messages: icuMessages,
+      defaultRichTextElements: {
+        emoji: renderEmoji,
+      },
+    },
+    intlCache
+  );
+  return intl;
+}
+
+export function setupI18n(
+  locale: string,
+  messages: LocaleMessagesType
+): LocalizerType {
+  if (!locale) {
+    throw new Error('i18n: locale parameter is required');
+  }
+  if (!messages) {
+    throw new Error('i18n: messages parameter is required');
+  }
+
+  const intl = createCachedIntl(locale, filterLegacyMessages(messages));
+
+  const localizer: LocalizerType = (key, substitutions) => {
+    strictAssert(
+      !localizer.isLegacyFormat(key),
+      `i18n: Legacy message format is no longer supported "${key}"`
+    );
+
+    strictAssert(
+      !Array.isArray(substitutions),
+      `i18n: Substitutions must be an object for ICU message "${key}"`
+    );
+
+    const result = intl.formatMessage({ id: key }, substitutions);
+
+    strictAssert(
+      typeof result === 'string',
+      'i18n: Formatted translation result must be a string, must use <Intl/> component to render JSX'
+    );
+
+    strictAssert(result !== key, `i18n: missing translation for "${key}"`);
+
+    return result;
+  };
+
+  localizer.getIntl = () => {
+    return intl;
+  };
+  localizer.isLegacyFormat = (key: string) => {
+    return !key.startsWith('icu:');
+  };
+  localizer.getLocale = () => locale;
+  localizer.getLocaleMessages = () => messages;
+  localizer.getLocaleDirection = () => {
+    return window.getResolvedMessagesLocaleDirection();
+  };
+
+  return localizer;
+}

yarn.lock

@@ -8949,6 +8949,21 @@ evp_bytestokey@^1.0.0, evp_bytestokey@^1.0.3:
     md5.js "^1.3.4"
     safe-buffer "^5.1.1"
 
+execa@5.1.1, execa@^5.1.1:
+  version "5.1.1"
+  resolved "https://registry.yarnpkg.com/execa/-/execa-5.1.1.tgz#f80ad9cbf4298f7bd1d4c9555c21e93741c411dd"
+  integrity sha512-8uSpZZocAZRBAPIEINJj3Lo9HyGitllczc27Eh5YYojjMFMn8yHMDMaUHE2Jqfq05D/wucwI4JGURyXt1vchyg==
+  dependencies:
+    cross-spawn "^7.0.3"
+    get-stream "^6.0.0"
+    human-signals "^2.1.0"
+    is-stream "^2.0.0"
+    merge-stream "^2.0.0"
+    npm-run-path "^4.0.1"
+    onetime "^5.1.2"
+    signal-exit "^3.0.3"
+    strip-final-newline "^2.0.0"
+
 execa@^0.7.0:
   version "0.7.0"
   resolved "https://registry.yarnpkg.com/execa/-/execa-0.7.0.tgz#944becd34cc41ee32a63a9faf27ad5a65fc59777"
@@ -8991,21 +9006,6 @@ execa@^5.0.0:
     signal-exit "^3.0.3"
     strip-final-newline "^2.0.0"
 
-execa@^5.1.1:
-  version "5.1.1"
-  resolved "https://registry.yarnpkg.com/execa/-/execa-5.1.1.tgz#f80ad9cbf4298f7bd1d4c9555c21e93741c411dd"
-  integrity sha512-8uSpZZocAZRBAPIEINJj3Lo9HyGitllczc27Eh5YYojjMFMn8yHMDMaUHE2Jqfq05D/wucwI4JGURyXt1vchyg==
-  dependencies:
-    cross-spawn "^7.0.3"
-    get-stream "^6.0.0"
-    human-signals "^2.1.0"
-    is-stream "^2.0.0"
-    merge-stream "^2.0.0"
-    npm-run-path "^4.0.1"
-    onetime "^5.1.2"
-    signal-exit "^3.0.3"
-    strip-final-newline "^2.0.0"
-
 expand-brackets@^0.1.4:
   version "0.1.5"
   resolved "https://registry.yarnpkg.com/expand-brackets/-/expand-brackets-0.1.5.tgz#df07284e342a807cd733ac5af72411e581d1177b"
@@ -14003,6 +14003,13 @@ p-finally@^2.0.0:
   resolved "https://registry.yarnpkg.com/p-finally/-/p-finally-2.0.1.tgz#bd6fcaa9c559a096b680806f4d657b3f0f240561"
   integrity sha512-vpm09aKwq6H9phqRQzecoDpD8TmVyGw70qmWlyq5onxY7tqyTTFVvxMykxQSQKILBSFlbXpypIw2T1Ml7+DDtw==
 
+p-limit@3.1.0, p-limit@^3.0.2, p-limit@^3.1.0:
+  version "3.1.0"
+  resolved "https://registry.yarnpkg.com/p-limit/-/p-limit-3.1.0.tgz#e1daccbe78d0d1388ca18c64fea38e3e57e3706b"
+  integrity sha512-TYOanM3wGwNGsZN2cVTYPArw454xnXj5qmWF1bEoAc4+cU/ol7GVh7odevjp1FNHduHc3KZMcFduxU5Xc6uJRQ==
+  dependencies:
+    yocto-queue "^0.1.0"
+
 p-limit@^1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/p-limit/-/p-limit-1.1.0.tgz#b07ff2d9a5d88bec806035895a2bab66a27988bc"
@@ -14021,13 +14028,6 @@ p-limit@^2.1.0:
   dependencies:
     p-try "^2.0.0"
 
-p-limit@^3.0.2, p-limit@^3.1.0:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/p-limit/-/p-limit-3.1.0.tgz#e1daccbe78d0d1388ca18c64fea38e3e57e3706b"
-  integrity sha512-TYOanM3wGwNGsZN2cVTYPArw454xnXj5qmWF1bEoAc4+cU/ol7GVh7odevjp1FNHduHc3KZMcFduxU5Xc6uJRQ==
-  dependencies:
-    yocto-queue "^0.1.0"
-
 p-locate@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/p-locate/-/p-locate-2.0.0.tgz#20a0103b222a70c8fd39cc2e580680f3dde5ec43"