feat: replace isIntlSupported with isNumberFormatSupported and add isNumberFormatToPartsSupported

This makes it clearer what these constants do. This change also makes the check itself safer.

Author: connor-baer

README.md

@@ -314,12 +314,20 @@ resolveCurrencyFormat('en-GB', { currencyDisplay: 'name' });
 
 ### Constants
 
-#### `isIntlSupported`
+#### `isNumberFormatSupported`
 
 Whether the `Intl` and `Intl.NumberFormat` APIs are supported by the runtime.
 
 ```ts
-const isIntlSupported: boolean;
+const isNumberFormatSupported: boolean;
+```
+
+#### `isNumberFormatToPartsSupported`
+
+Whether the `Intl`, `Intl.NumberFormat`, and `Intl.NumberFormat.formatToParts` APIs are supported by the runtime.
+
+```ts
+const isNumberFormatToPartsSupported: boolean;
 ```
 
 #### `CURRENCIES`

src/base.ts

@@ -14,7 +14,11 @@
  */
 
 import { Locale, Options, Format } from './types';
-import { isIntlSupported, getNumberFormat } from './lib/intl';
+import {
+  isNumberFormatSupported,
+  isNumberFormatToPartsSupported,
+  getNumberFormat,
+} from './lib/intl';
 import { findIndex } from './lib/findIndex';
 
 type Args = Array<unknown>;
@@ -26,7 +30,7 @@ type GetOptions<T extends Args> = (
 
 export function formatFactory<T extends Args>(getOptions: GetOptions<T>) {
   return (value: number, locales?: Locale | Locale[], ...args: T): string => {
-    if (!isIntlSupported) {
+    if (!isNumberFormatSupported) {
       return `${value}`;
     }
 
@@ -44,10 +48,7 @@ export function formatToPartsFactory<T extends Args>(
     locales?: Locale | Locale[],
     ...args: T
   ): Intl.NumberFormatPart[] => {
-    if (
-      !isIntlSupported ||
-      typeof Intl.NumberFormat.prototype.formatToParts === 'undefined'
-    ) {
+    if (!isNumberFormatToPartsSupported) {
       return [{ type: 'integer', value: value.toString() }];
     }
 
@@ -67,10 +68,7 @@ export function resolveFormatFactory<T extends Args>(
   getOptions: GetOptions<T>,
 ) {
   return (locales?: Locale | Locale[], ...args: T): Format | null => {
-    if (
-      !isIntlSupported ||
-      typeof Intl.NumberFormat.prototype.formatToParts === 'undefined'
-    ) {
+    if (!isNumberFormatToPartsSupported) {
       return null;
     }
 

src/index.ts

@@ -24,7 +24,11 @@ import {
 import { getDecimalOptions } from './lib/numbers';
 import { getCurrencyOptions } from './lib/currencies';
 
-export { isIntlSupported } from './lib/intl';
+export {
+  isNumberFormatSupported,
+  isNumberFormatToPartsSupported,
+  isIntlSupported,
+} from './lib/intl';
 export { CURRENCIES } from './data/currencies';
 
 type NumberArgs = [Intl.NumberFormatOptions?];

src/lib/intl.ts

@@ -18,10 +18,48 @@ import memoizeFormatConstructor from 'intl-format-cache';
 import { Locale } from '../types';
 
 /**
- * Whether the `Intl` and `Intl.NumberFormat` APIs are supported by the runtime.
+ * Whether the `Intl` and `Intl.NumberFormat` APIs
+ * are supported by the runtime.
  */
-export const isIntlSupported =
-  typeof Intl !== 'undefined' && typeof Intl.NumberFormat !== 'undefined';
+export const isNumberFormatSupported = (() => {
+  try {
+    return (
+      typeof Intl !== 'undefined' && typeof Intl.NumberFormat !== 'undefined'
+    );
+  } catch (error) {
+    return false;
+  }
+})();
+
+/**
+ * Whether the `Intl`, `Intl.NumberFormat`, and
+ * `Intl.NumberFormat.formatToParts` APIs are supported by the runtime.
+ */
+export const isNumberFormatToPartsSupported = (() => {
+  try {
+    return typeof Intl.NumberFormat.prototype.formatToParts !== 'undefined';
+  } catch (error) {
+    return false;
+  }
+})();
+
+/**
+ * @deprecated Whether the `Intl` and `Intl.NumberFormat` APIs
+ * are supported by the runtime.
+ */
+export const isIntlSupported = (() => {
+  if (process.env.NODE_ENV !== 'production') {
+    // eslint-disable-next-line no-console
+    console.warn(
+      [
+        'DEPRECATED: isIntlSupported has been replaced',
+        'by isNumberFormatSupported & isNumberFormatToPartsSupported',
+        'and will be removed in the next major version.',
+      ].join(' '),
+    );
+  }
+  return isNumberFormatSupported;
+})();
 
 export const getNumberFormat: (
   locales?: Locale | Locale[],