Generate TypeScript definition file

package.json

@@ -17,12 +17,16 @@
 	],
 	"module": "lib/icu-message-formatter.es.js",
 	"main": "lib/icu-message-formatter.cjs.js",
+	"types": "types/IcuMessageFormatter.d.ts",
 	"sideEffects": false,
 	"scripts": {
 		"format": "eslint --fix \"**/*.js\"",
 		"lint": "eslint \"**/*.js\"",
 		"test": "jest",
-		"build": "rollup --config --bundleConfigAsCjs && rollup --config rollup.config.dist.js --bundleConfigAsCjs",
+		"build": "npm run build:lib && npm run build:dist && npm run build:dts",
+		"build:lib": "rollup --config --bundleConfigAsCjs",
+		"build:dist": "rollup --config rollup.config.dist.js --bundleConfigAsCjs",
+		"build:dts": "tsc",
 		"prepublishOnly": "npm run build"
 	},
 	"dependencies": {
@@ -50,7 +54,8 @@
 		"eslint-plugin-import": "^2.28.1",
 		"eslint-plugin-jsdoc": "^46.5.1",
 		"jest": "^29.6.4",
-		"rollup": "^3.29.0"
+		"rollup": "^3.29.0",
+		"typescript": "^5.2.2"
 	},
 	"engines": {
 		"node": ">=18"

source/MessageFormatter.js

@@ -32,7 +32,7 @@ import {memoize} from '@ultraq/function-utils';
 
 /**
  * @template T
- * @callback TypeHandler<T>
+ * @callback TypeHandler
  * @param {string} value
  * @param {string} matches
  * @param {string} locale
@@ -53,7 +53,7 @@ export default class MessageFormatter {
 	 * you register.
 	 * 
 	 * @param {string} locale
-	 * @param {Record<string,TypeHandler<*>>} [typeHandlers={}]
+	 * @param {Record<string,TypeHandler<any>>} typeHandlers
 	 *   Optional object where the keys are the names of the types to register,
 	 *   their values being the functions that will return a nicely formatted
 	 *   string for the data and locale they are given.
@@ -68,14 +68,12 @@ export default class MessageFormatter {
 	 * Formats an ICU message syntax string using `values` for placeholder data
 	 * and any currently-registered type handlers.
 	 * 
-	 * @param {string} message
-	 * @param {FormatValues} [values={}]
-	 * @return {string}
+	 * @type {FormatFunction}
 	 */
 	format = memoize((message, values = {}) => {
 
 		return flatten(this.process(message, values)).join('');
-	})
+	});
 
 	/**
 	 * Process an ICU message syntax string using `values` for placeholder data
@@ -89,7 +87,7 @@ export default class MessageFormatter {
 	 * string renderer.
 	 * 
 	 * @param {string} message
-	 * @param {FormatValues} [values={}]
+	 * @param {FormatValues} values
 	 * @return {Array<any>}
 	 */
 	process(message, values = {}) {

source/pluralTypeHandler.js

@@ -69,15 +69,10 @@ function replaceNumberSign(caseBody, value) {
  * See https://formatjs.io/docs/core-concepts/icu-syntax#plural-format for more
  * details on how the `plural` statement works.
  * 
- * @param {string} value
- * @param {string} matches
- * @param {string} locale
- * @param {FormatValues} values
- * @param {FormatFunction} format
- * @return {string}
+ * @type {TypeHandler<string>}
  */
 export default function pluralTypeHandler(value, matches = '', locale, values, format) {
-	const { args, cases } = parseCases(matches);
+	const {args, cases} = parseCases(matches);
 
 	let intValue = parseInt(value);
 
@@ -110,7 +105,7 @@ export default function pluralTypeHandler(value, matches = '', locale, values, f
 	for (let i = 0; i < keywordPossibilities.length; i++) {
 		const keyword = keywordPossibilities[i];
 		if (keyword in cases) {
-			const { caseBody, numberValues } = replaceNumberSign(cases[keyword], intValue);
+			const {caseBody, numberValues} = replaceNumberSign(cases[keyword], intValue);
 			return format(caseBody, {
 				...values,
 				...numberValues

source/selectTypeHandler.js

@@ -33,7 +33,7 @@ const OTHER = 'other';
  * @return {string}
  */
 export default function selectTypeHandler(value, matches = '', locale, values, format) {
-	const { cases } = parseCases(matches);
+	const {cases} = parseCases(matches);
 
 	if (value in cases) {
 		return format(cases[value], values);

source/selectTypeHandler.test.js

@@ -31,12 +31,12 @@ describe('selectTypeHandler', function() {
 		let message = '{mood, select, happy {Good} sad {bad} other {Ambivalent}} morning';
 
 		test('Explicit branch', function() {
-			let result = formatter.format(message, { mood: 'happy' });
+			let result = formatter.format(message, {mood: 'happy'});
 			expect(result).toBe('Good morning');
 		});
 
 		test('Fallback branch', function() {
-			let result = formatter.format(message, { mood: 'angry' });
+			let result = formatter.format(message, {mood: 'angry'});
 			expect(result).toBe('Ambivalent morning');
 		});
 	});
@@ -45,7 +45,7 @@ describe('selectTypeHandler', function() {
 
 		test('No matching branch', function() {
 			let message = 'I am feeling {mood, select, happy {good}}';
-			let result = formatter.format(message, { mood: 'ambivalent' });
+			let result = formatter.format(message, {mood: 'ambivalent'});
 			expect(result).toBe('I am feeling ambivalent');
 		});
 	});

source/utilities.js

@@ -151,7 +151,7 @@ export function splitFormattedArgument(block) {
  * @param {string} string
  * @param {string} separator
  * @param {number} limit
- * @param {string[]} [accumulator=[]]
+ * @param {string[]} accumulator
  * @return {string[]}
  */
 function split(string, separator, limit, accumulator = []) {

source/utilities.test.js

@@ -15,7 +15,7 @@
  */
 
 /* eslint-env jest */
-import { parseCases } from './utilities';
+import {parseCases} from './utilities';
 
 /**
  * Tests for the `parseCases` util.
@@ -45,13 +45,13 @@ describe('parseCases', function() {
 		test('multiple cases', function() {
 			let result = parseCases('key1 {case1} key2 {case2} key3 {case3}');
 			expect(result.args).toStrictEqual([]);
-			expect(result.cases).toStrictEqual({ key1: 'case1', key2: 'case2', key3: 'case3' });
+			expect(result.cases).toStrictEqual({key1: 'case1', key2: 'case2', key3: 'case3'});
 		});
 
 		test('multiple cases with symbols', function() {
 			let result = parseCases('=key1 {case1} &key2 {case2} key3 {case3}');
 			expect(result.args).toStrictEqual([]);
-			expect(result.cases).toStrictEqual({ '=key1': 'case1', '&key2': 'case2', key3: 'case3' });
+			expect(result.cases).toStrictEqual({'=key1': 'case1', '&key2': 'case2', key3: 'case3'});
 		});
 
 		test('multiple cases with inconsistent whitespace', function() {
@@ -61,13 +61,13 @@ describe('parseCases', function() {
     key2 {case2}
                                 key3 {case3}`);
 			expect(result.args).toStrictEqual([]);
-			expect(result.cases).toStrictEqual({ key1: 'case1', key2: 'case2', key3: 'case3' });
+			expect(result.cases).toStrictEqual({key1: 'case1', key2: 'case2', key3: 'case3'});
 		});
 
 		test('multiple cases with minimal whitespace', function() {
 			let result = parseCases(`key1{case1}key2{case2}key3{case3}`);
 			expect(result.args).toStrictEqual([]);
-			expect(result.cases).toStrictEqual({ key1: 'case1', key2: 'case2', key3: 'case3' });
+			expect(result.cases).toStrictEqual({key1: 'case1', key2: 'case2', key3: 'case3'});
 		});
 
 		test('multiple cases with complex bodies', function() {
@@ -77,7 +77,7 @@ describe('parseCases', function() {
     key2 {=key1 {case1} &key2 {case2} key3 {case3}}
                                 key3 {}`);
 			expect(result.args).toStrictEqual([]);
-			expect(result.cases).toStrictEqual({ key1: '{}{}{}{{{{}}}}', key2: '=key1 {case1} &key2 {case2} key3 {case3}', key3: '' });
+			expect(result.cases).toStrictEqual({key1: '{}{}{}{{{{}}}}', key2: '=key1 {case1} &key2 {case2} key3 {case3}', key3: ''});
 		});
 	});
 

tsconfig.json

@@ -0,0 +1,11 @@
+{
+	"include": ["source/**/*.js"],
+	"exclude": ["source/**/*.test.js"],
+	"compilerOptions": {
+		"allowJs": true,
+		"declaration": true,
+		"declarationMap": true,
+		"emitDeclarationOnly": true,
+		"outFile": "lib/icu-message-formatter.d.ts"
+	}
+}