fix(mf2): Always use locale set in function context

Author: XM5jDcsHTyGJtQqlCi

mf2/messageformat/src/functions/datetime.ts

@@ -3,12 +3,7 @@ import { MessageResolutionError } from '../errors.js';
 import type { MessageExpressionPart } from '../formatted-parts.js';
 import type { MessageValue } from '../message-value.js';
 import type { MessageFunctionContext } from '../resolve/function-context.js';
-import {
-  asBoolean,
-  asPositiveInteger,
-  asString,
-  mergeLocales
-} from './utils.js';
+import { asBoolean, asPositiveInteger, asString } from './utils.js';
 
 /** @beta */
 export interface MessageDateTime extends MessageValue {
@@ -51,7 +46,7 @@ export const datetime = (
   options: Record<string, unknown>,
   input?: unknown
 ): MessageDateTime =>
-  dateTimeImplementation(ctx, options, input, res => {
+  dateTimeImplementation(ctx, input, res => {
     for (const [name, value] of Object.entries(options)) {
       if (value === undefined) continue;
       try {
@@ -91,7 +86,7 @@ export const date = (
   options: Record<string, unknown>,
   input?: unknown
 ): MessageDateTime =>
-  dateTimeImplementation(ctx, options, input, res => {
+  dateTimeImplementation(ctx, input, res => {
     const ds = options.style ?? res.dateStyle ?? 'medium';
     for (const name of Object.keys(res)) {
       if (!localeOptions.includes(name)) delete res[name];
@@ -115,7 +110,7 @@ export const time = (
   options: Record<string, unknown>,
   input?: unknown
 ): MessageDateTime =>
-  dateTimeImplementation(ctx, options, input, res => {
+  dateTimeImplementation(ctx, input, res => {
     const ts = options.style ?? res.timeStyle ?? 'short';
     for (const name of Object.keys(res)) {
       if (!localeOptions.includes(name)) delete res[name];
@@ -130,12 +125,10 @@ export const time = (
 
 function dateTimeImplementation(
   ctx: MessageFunctionContext,
-  options: Record<string, unknown>,
   input: unknown,
   parseOptions: (res: Record<string, unknown>) => void
 ): MessageDateTime {
   const { localeMatcher, locales, source } = ctx;
-  const lc = mergeLocales(locales, input, options);
   const opt: Intl.DateTimeFormatOptions = { localeMatcher };
   if (input && typeof input === 'object') {
     if (input && 'options' in input) Object.assign(opt, input.options);
@@ -174,13 +167,16 @@ function dateTimeImplementation(
       return dir;
     },
     get locale() {
-      return (locale ??= Intl.DateTimeFormat.supportedLocalesOf(lc, opt)[0]);
+      return (locale ??= Intl.DateTimeFormat.supportedLocalesOf(
+        locales,
+        opt
+      )[0]);
     },
     get options() {
       return { ...opt };
     },
     toParts() {
-      dtf ??= new Intl.DateTimeFormat(lc, opt);
+      dtf ??= new Intl.DateTimeFormat(locales, opt);
       const parts = dtf.formatToParts(date);
       locale ??= dtf.resolvedOptions().locale;
       dir ??= getLocaleDir(locale);
@@ -189,7 +185,7 @@ function dateTimeImplementation(
         : [{ type: 'datetime', source, locale, parts }];
     },
     toString() {
-      dtf ??= new Intl.DateTimeFormat(lc, opt);
+      dtf ??= new Intl.DateTimeFormat(locales, opt);
       str ??= dtf.format(date);
       return str;
     },

mf2/messageformat/src/functions/number.ts

@@ -3,7 +3,7 @@ import { MessageResolutionError } from '../errors.js';
 import type { MessageExpressionPart } from '../formatted-parts.js';
 import type { MessageValue } from '../message-value.js';
 import type { MessageFunctionContext } from '../resolve/function-context.js';
-import { asPositiveInteger, asString, mergeLocales } from './utils.js';
+import { asPositiveInteger, asString } from './utils.js';
 
 /** @beta */
 export interface MessageNumber extends MessageValue {
@@ -80,7 +80,7 @@ export function number(
   exprOpt: Record<string | symbol, unknown>,
   operand?: unknown
 ): MessageNumber {
-  const { source } = ctx;
+  const { locales, source } = ctx;
   const options: Intl.NumberFormatOptions &
     Intl.PluralRulesOptions & { select?: 'exact' | 'cardinal' | 'ordinal' } = {
     localeMatcher: ctx.localeMatcher
@@ -126,7 +126,6 @@ export function number(
       ? Math.round(value as number)
       : value;
 
-  const lc = mergeLocales(ctx.locales, operand, exprOpt);
   let locale: string | undefined;
   let dir = ctx.dir;
   let nf: Intl.NumberFormat | undefined;
@@ -140,7 +139,10 @@ export function number(
       return dir;
     },
     get locale() {
-      return (locale ??= Intl.NumberFormat.supportedLocalesOf(lc, options)[0]);
+      return (locale ??= Intl.NumberFormat.supportedLocalesOf(
+        locales,
+        options
+      )[0]);
     },
     get options() {
       return { ...options };
@@ -153,11 +155,11 @@ export function number(
         ? { ...options, select: undefined, type: options.select }
         : options;
       // Intl.PluralRules needs a number, not bigint
-      cat ??= new Intl.PluralRules(lc, pluralOpt).select(Number(num));
+      cat ??= new Intl.PluralRules(locales, pluralOpt).select(Number(num));
       return keys.has(cat) ? cat : null;
     },
     toParts() {
-      nf ??= new Intl.NumberFormat(lc, options);
+      nf ??= new Intl.NumberFormat(locales, options);
       const parts = nf.formatToParts(num);
       locale ??= nf.resolvedOptions().locale;
       dir ??= getLocaleDir(locale);
@@ -166,7 +168,7 @@ export function number(
         : [{ type: 'number', source, locale, parts }];
     },
     toString() {
-      nf ??= new Intl.NumberFormat(lc, options);
+      nf ??= new Intl.NumberFormat(locales, options);
       str ??= nf.format(num);
       return str;
     },

mf2/messageformat/src/functions/string.ts

@@ -1,7 +1,6 @@
 import type { MessageExpressionPart } from '../formatted-parts.js';
 import type { MessageValue } from '../message-value.js';
 import type { MessageFunctionContext } from '../resolve/function-context.js';
-import { mergeLocales } from './utils.js';
 
 /** @beta */
 export interface MessageString extends MessageValue {
@@ -31,12 +30,12 @@ export interface MessageStringPart extends MessageExpressionPart {
  * @beta */
 export function string(
   ctx: Pick<MessageFunctionContext, 'dir' | 'locales' | 'source'>,
-  options: Record<string, unknown>,
+  _options: Record<string, unknown>,
   input?: unknown
 ): MessageString {
   const str = input === undefined ? '' : String(input);
   const selStr = str.normalize();
-  const [locale] = mergeLocales(ctx.locales, input, options);
+  const locale = ctx.locales[0];
   return {
     type: 'string',
     source: ctx.source,

mf2/messageformat/src/functions/utils.ts

@@ -20,7 +20,7 @@ export function asBoolean(value: unknown): boolean {
 
 /**
  * Utility function for custom functions.
- * Cast a value as a positive integer,
+ * Cast a value as a non-negative integer,
  * unwrapping objects using their `valueOf()` methods.
  * Also accepts JSON string reprentations of integers.
  * Throws a `RangeError` for invalid inputs.
@@ -53,39 +53,3 @@ export function asString(value: unknown): string {
   if (value && typeof value === 'object') return String(value);
   throw new RangeError('Not a string');
 }
-
-/**
- * Utility function for custom functions.
- * Merge the locales set for the message,
- * an `options` property on the input,
- * and the `locale` option of the expression.
- *
- * @beta
- */
-export function mergeLocales(
-  locales: string[],
-  input: unknown,
-  options: Record<string, unknown> | null
-): string[] {
-  // Message locales are always included, but have the lowest precedence
-  let lc = locales;
-
-  // Next, use options from input object
-  if (input && typeof input === 'object' && 'locale' in input) {
-    if (typeof input.locale === 'string') {
-      lc = [input.locale, ...lc];
-    } else if (
-      Array.isArray(input.locale) &&
-      input.locale.every(lc => typeof lc === 'string')
-    ) {
-      lc = [...input.locale, ...lc];
-    }
-  }
-
-  // Explicit locale in expression options is preferred over all others
-  if (options?.locale) {
-    lc = [...asString(options.locale).split(','), ...lc];
-  }
-
-  return lc;
-}

mf2/messageformat/src/resolve/function-ref.test.ts

@@ -62,17 +62,18 @@ describe('inputs with options', () => {
     expect(parts).toEqual(nf.formatToParts(12345678));
   });
 
-  test('MessageValue locales take precedence', () => {
+  test('u:locale value take precedence', () => {
     const mf = new MessageFormat(
       'en',
-      '{$val :number minimumFractionDigits=2}'
+      '{$val :number minimumFractionDigits=2 u:locale=ar}'
     );
-    const val = Object.assign(new Number(12345), { locale: 'fi' });
-    const msg = mf.formatToParts({ val });
-    const { parts } = msg[0] as MessageNumberPart;
+    const msg = mf.formatToParts({ val: 12345 });
+    const { parts } = msg[1] as MessageNumberPart;
 
-    const nf = new Intl.NumberFormat('fi', { minimumFractionDigits: 2 });
-    expect(parts).toEqual(nf.formatToParts(12345));
+    const ar = new Intl.NumberFormat('ar', { minimumFractionDigits: 2 });
+    const en = new Intl.NumberFormat('en', { minimumFractionDigits: 2 });
+    expect(parts).toEqual(ar.formatToParts(12345));
+    expect(parts).not.toEqual(en.formatToParts(12345));
   });
 });