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Merged
merged 8 commits into from
May 14, 2025
Merged

i18n-calypso: Replace EventEmitter with simplified subscriber callbacks #103304

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41b17d5
Convert i18n events handling to subscriber model
aduth May 9, 2025
7cd2a08
Add additional test coverage
aduth May 9, 2025
ee3e0bb
Microoptimize subscriber removal
aduth May 9, 2025
b0355f1
Update changelog for i18n-calypso
aduth May 9, 2025
9f26ca1
Remove types for eliminated methods
aduth May 9, 2025
d8589a6
Use Set as internal representation for subscribers
aduth May 14, 2025
d29692b
Omit emitChange from public types API
aduth May 14, 2025
e8ea58b
Remove duplicative test on subscriber calls
aduth May 14, 2025
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6 changes: 1 addition & 5 deletions client/components/calypso-i18n-provider/index.tsx
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Expand Up @@ -19,11 +19,7 @@ const CalypsoI18nProvider: FunctionComponent< { i18n?: I18N; children?: React.Re
setLocaleSlug( i18n.getLocaleSlug() );
};

i18n.on( 'change', onChange );

return () => {
i18n.off( 'change', onChange );
};
return i18n.subscribe( onChange );
}, [ i18n ] );

useEffect( () => {
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4 changes: 2 additions & 2 deletions client/components/community-translator/index.jsx
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Expand Up @@ -31,11 +31,11 @@ class CommunityTranslator extends Component {
// callback when translated component changes.
// the callback is overwritten by the translator on load/unload, so we're returning it within an anonymous function.
i18n.registerComponentUpdateHook( () => {} );
i18n.on( 'change', this.refresh );
this.i18nUnsubscribe = i18n.subscribe( this.refresh );
}

componentWillUnmount() {
i18n.off( 'change', this.refresh );
this.i18nUnsubscribe();
}

setLanguage() {
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4 changes: 2 additions & 2 deletions client/layout/community-translator/launcher.jsx
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Expand Up @@ -59,12 +59,12 @@ class TranslatorLauncher extends Component {
highlightRef = createRef();

componentDidMount() {
i18n.on( 'change', this.onI18nChange );
this.i18nUnsubscribe = i18n.subscribe( this.onI18nChange );
window.addEventListener( 'keydown', this.handleKeyDown );
}

componentWillUnmount() {
i18n.off( 'change', this.onI18nChange );
this.i18nUnsubscribe();
window.removeEventListener( 'keydown', this.handleKeyDown );
}

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2 changes: 1 addition & 1 deletion client/lib/i18n-utils/empathy-mode.js
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Expand Up @@ -3,7 +3,7 @@ import i18n, { I18N, translate } from 'i18n-calypso';
let defaultUntranslatedPlacehoder = translate( "I don't understand" );

// keep `defaultUntranslatedPlacehoder` in sync with i18n changes
i18n.on( 'change', () => {
i18n.subscribe( () => {
defaultUntranslatedPlacehoder = translate( "I don't understand" );
} );

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2 changes: 1 addition & 1 deletion client/lib/translator-jumpstart/index.js
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Expand Up @@ -328,6 +328,6 @@ export function trackTranslatorStatus( isTranslatorEnabled ) {
}

// re-initialize when new locale data is loaded
i18n.on( 'change', communityTranslatorJumpstart.init.bind( communityTranslatorJumpstart ) );
i18n.subscribe( communityTranslatorJumpstart.init.bind( communityTranslatorJumpstart ) );
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The call of the init method, does it even work? The method takes two args, user and isUserSettingsReady. And returns early if user is null-ish. But the change event listener was not called with any arguments, is it? And neither is the new subscribe callback.

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The call of the init method, does it even work? The method takes two args, user and isUserSettingsReady. And returns early if user is null-ish. But the change event listener was not called with any arguments, is it? And neither is the new subscribe callback.

I'll check on this tomorrow 👍

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The call of the init method, does it even work? The method takes two args, user and isUserSettingsReady. And returns early if user is null-ish. But the change event listener was not called with any arguments, is it? And neither is the new subscribe callback.

I'll check on this tomorrow 👍

Update: You're correct that the initialization triggered by this subscriber always short-circuits at the user check. This subscriber is very old (originates in pre-OSS version), at which time the init function didn't take arguments. Additionally, I don't think we should rely on a side-effect like this when importing a module, since it isn't compatible with tree-shaking. That being said, the subscriber is being added.

Instead, I think the initialization is happening in the TranslatorLauncher component, which passes the user arguments correctly. It also appears to reinitialize many times when the component re-renders.

I'm not entirely familiar with how this should be working (e.g. in response to asynchronous loads or language changes), but I think it's fair to say that the subscriber is not doing anything in its current form and can be removed.

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I'm going to keep this in as-is to keep it functionally equivalent, and will follow-up with a pull request proposing to remove the ineffective subscribe call.


export default communityTranslatorJumpstart;
6 changes: 6 additions & 0 deletions packages/i18n-calypso/CHANGELOG.md
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@@ -1,3 +1,9 @@
## Trunk

- Breaking: Emitter object replaced with subscriber
- Before: `i18n.on( 'change', callback ); i18n.off( 'change', callback );`
- After: `const unsubscribe = i18n.subscribe( callback ); unsubscribe();`

## 7.5.0

- Add `translationOptions` to fixMe so it can work on translations with context.
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1 change: 0 additions & 1 deletion packages/i18n-calypso/package.json
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Expand Up @@ -29,7 +29,6 @@
"@tannin/sprintf": "^1.1.0",
"@wordpress/compose": "^7.23.0",
"debug": "^4.4.0",
"events": "^3.3.0",
"hash.js": "^1.1.7",
"lru": "^3.1.0",
"tannin": "^1.2.0",
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26 changes: 9 additions & 17 deletions packages/i18n-calypso/src/i18n.js
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@@ -1,4 +1,3 @@
import { EventEmitter } from 'events';
import interpolateComponents from '@automattic/interpolate-components';
import sprintf from '@tannin/sprintf';
import debugFactory from 'debug';
Expand Down Expand Up @@ -145,11 +144,7 @@ function I18N() {
};
this.componentUpdateHooks = [];
this.translateHooks = [];
this.stateObserver = new EventEmitter();
// Because the higher-order component can wrap a ton of React components,
// we need to bump the number of listeners to infinity and beyond
// FIXME: still valid?
this.stateObserver.setMaxListeners( 0 );
this.subscribers = new Set();
// default configuration
this.configure();
}
Expand Down Expand Up @@ -191,16 +186,13 @@ I18N.prototype.geolocateCurrencySymbol = async function ( callback ) {
callback?.( 'string' === typeof geoData?.country_short ? geoData.country_short : '' );
};

I18N.prototype.on = function ( ...args ) {
this.stateObserver.on( ...args );
I18N.prototype.subscribe = function ( callback ) {
this.subscribers.add( callback );
return () => this.subscribers.delete( callback );
};

I18N.prototype.off = function ( ...args ) {
this.stateObserver.off( ...args );
};

I18N.prototype.emit = function ( ...args ) {
this.stateObserver.emit( ...args );
I18N.prototype.emitChange = function () {
this.subscribers.forEach( ( callback ) => callback() );
};

/**
Expand Down Expand Up @@ -304,7 +296,7 @@ I18N.prototype.setLocale = function ( localeData ) {

this.state.tannin = new Tannin( { [ domain_key ]: this.state.locale } );

this.stateObserver.emit( 'change' );
this.emitChange();
};

I18N.prototype.getLocale = function () {
Expand Down Expand Up @@ -347,7 +339,7 @@ I18N.prototype.addTranslations = function ( localeData ) {
}
}

this.stateObserver.emit( 'change' );
this.emitChange();
};

/**
Expand Down Expand Up @@ -452,7 +444,7 @@ I18N.prototype.translate = function () {
*/
I18N.prototype.reRenderTranslations = function () {
debug( 'Re-rendering all translations due to external request' );
this.stateObserver.emit( 'change' );
this.emitChange();
};

I18N.prototype.registerComponentUpdateHook = function ( callback ) {
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4 changes: 0 additions & 4 deletions packages/i18n-calypso/src/index.ts
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Expand Up @@ -24,10 +24,6 @@ export const reRenderTranslations = i18n.reRenderTranslations.bind( i18n );
export const registerComponentUpdateHook = i18n.registerComponentUpdateHook.bind( i18n );
export const registerTranslateHook = i18n.registerTranslateHook.bind( i18n );
export const state = i18n.state;
export const stateObserver = i18n.stateObserver;
export const on = i18n.on.bind( i18n );
export const off = i18n.off.bind( i18n );
export const emit = i18n.emit.bind( i18n );
export const fixMe = i18n.fixMe.bind( i18n );

export type * from './types';
3 changes: 1 addition & 2 deletions packages/i18n-calypso/src/localize.js
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Expand Up @@ -19,8 +19,7 @@ export default function localize( ComposedComponent ) {
const [ counter, setCounter ] = useState( 0 );
useEffect( () => {
const onChange = () => setCounter( ( c ) => c + 1 );
i18n.on( 'change', onChange );
return () => i18n.off( 'change', onChange );
return i18n.subscribe( onChange );
}, [ i18n ] );

const i18nProps = useMemo( () => bindI18nProps( i18n, counter ), [ i18n, counter ] );
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5 changes: 2 additions & 3 deletions packages/i18n-calypso/src/rtl.js
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Expand Up @@ -12,8 +12,7 @@ export function useRtl() {
return i18n.isRtl();
},
subscribe( callback ) {
i18n.on( 'change', callback );
return () => i18n.off( 'change', callback );
return i18n.subscribe( callback );
},
} ),
[ i18n ]
Expand All @@ -24,7 +23,7 @@ export function useRtl() {

export const withRtl = createHigherOrderComponent(
( WrappedComponent ) =>
forwardRef( ( props, ref ) => {
forwardRef( function WrappedRtlComponent( props, ref ) {
const isRtl = useRtl();
return <WrappedComponent { ...props } isRtl={ isRtl } ref={ ref } />;
} ),
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76 changes: 76 additions & 0 deletions packages/i18n-calypso/src/test/index.js
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Expand Up @@ -24,6 +24,15 @@ describe( 'I18n', function () {
} );

describe( 'setLocale()', function () {
it( 'should emit a change event', () => {
const callback = jest.fn();
i18n.subscribe( callback );

i18n.setLocale();

expect( callback ).toHaveBeenCalled();
} );

describe( 'adding a new locale source from the same language', function () {
beforeEach( function () {
i18n.setLocale( {
Expand Down Expand Up @@ -191,13 +200,23 @@ describe( 'I18n', function () {

expect( translate( 'test-does-not-exist' ) ).toBe( 'translation3' );
} );

it( 'should return the new translation if it has been overwritten', function () {
i18n.addTranslations( {
'test-will-overwrite': [ 'not-translation1' ],
} );

expect( translate( 'test-will-overwrite' ) ).toBe( 'not-translation1' );
} );

it( 'should emit a change event', () => {
const callback = jest.fn();
i18n.subscribe( callback );

i18n.addTranslations( {} );

expect( callback ).toHaveBeenCalled();
} );
} );
} );

Expand Down Expand Up @@ -266,6 +285,63 @@ describe( 'I18n', function () {
} );
} );

describe( 'emitChange()', () => {
it( 'should call all subscribed callbacks', () => {
const callback1 = jest.fn();
const callback2 = jest.fn();

i18n.subscribe( callback1 );
i18n.subscribe( callback2 );

i18n.emitChange();

expect( callback1 ).toHaveBeenCalled();
expect( callback2 ).toHaveBeenCalled();
} );

it( 'should not call unsubscribed callbacks', () => {
const callback1 = jest.fn();
const callback2 = jest.fn();
const callback3 = jest.fn();

i18n.subscribe( callback1 );
const unsubscribe2 = i18n.subscribe( callback2 );
i18n.subscribe( callback3 );

unsubscribe2();
i18n.emitChange();

expect( callback1 ).toHaveBeenCalled();
expect( callback2 ).not.toHaveBeenCalled();
expect( callback3 ).toHaveBeenCalled();
} );
} );

describe( 'reRenderTranslations()', () => {
it( 'should call subscriber callback', () => {
const callback = jest.fn();

i18n.subscribe( callback );

i18n.reRenderTranslations();

expect( callback ).toHaveBeenCalled();
} );
} );

describe( 'subscribe()', () => {
it( 'should return an unsubscribe function', () => {
const callback = jest.fn();

const unsubscribe = i18n.subscribe( callback );
unsubscribe();

i18n.setLocale();

expect( callback ).not.toHaveBeenCalled();
} );
} );

describe( 'hashed locale data', function () {
it( 'should find keys when looked up by simple hash', function () {
i18n.setLocale( {
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7 changes: 1 addition & 6 deletions packages/i18n-calypso/src/types/index.d.ts
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Expand Up @@ -132,9 +132,7 @@ export interface I18N {
registerTranslateHook( hook: TranslateHook ): void;
registerComponentUpdateHook( hook: ComponentUpdateHook ): void;

on( eventName: string, listener: EventListener ): void;
off( eventName: string, listener: EventListener ): void;
emit( eventName: string, ...payload: any ): void;
subscribe( callback: () => any ): () => void;

/**
* Returns `newCopy` if given `text` is translated or locale is English, otherwise returns the `oldCopy`.
Expand Down Expand Up @@ -180,9 +178,6 @@ export declare const isRtl: typeof i18n.isRtl;
export declare const defaultLocaleSlug: typeof i18n.defaultLocaleSlug;
export declare const registerTranslateHook: typeof i18n.registerTranslateHook;
export declare const registerComponentUpdateHook: typeof i18n.registerComponentUpdateHook;
export declare const on: typeof i18n.on;
export declare const off: typeof i18n.off;
export declare const emit: typeof i18n.emit;
export declare const fixMe: typeof i18n.fixMe;

export interface LocalizeProps {
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3 changes: 1 addition & 2 deletions packages/i18n-calypso/src/use-translate.js
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Expand Up @@ -13,8 +13,7 @@ export default function useTranslate() {

useEffect( () => {
const onChange = () => setCounter( ( c ) => c + 1 );
i18n.on( 'change', onChange );
return () => i18n.off( 'change', onChange );
return i18n.subscribe( onChange );
}, [ i18n ] );

return useMemo( () => bindTranslate( i18n, counter ), [ i18n, counter ] );
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1 change: 0 additions & 1 deletion yarn.lock
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Expand Up @@ -21885,7 +21885,6 @@ __metadata:
"@types/react": "npm:^18.3.20"
"@wordpress/compose": "npm:^7.23.0"
debug: "npm:^4.4.0"
events: "npm:^3.3.0"
hash.js: "npm:^1.1.7"
lru: "npm:^3.1.0"
react: "npm:^18.3.1"
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