ICU types

ts/util/getICUMessageParams.ts

@@ -0,0 +1,83 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { TYPE, parse } from '@formatjs/icu-messageformat-parser';
+import type {
+  MessageFormatElement,
+  PluralOrSelectOption,
+} from '@formatjs/icu-messageformat-parser';
+import { missingCaseError } from './missingCaseError';
+
+export type ICUMessageParamType = Readonly<
+  | {
+      type: 'string' | 'date' | 'number' | 'jsx' | 'time';
+    }
+  | {
+      type: 'select';
+      validOptions: ReadonlyArray<string>;
+    }
+>;
+
+export function getICUMessageParams(
+  message: string,
+  defaultRichTextElementNames: Array<string> = []
+): Map<string, ICUMessageParamType> {
+  const params = new Map();
+
+  function visitOptions(options: Record<string, PluralOrSelectOption>) {
+    for (const option of Object.values(options)) {
+      visit(option.value);
+    }
+  }
+
+  function visit(elements: ReadonlyArray<MessageFormatElement>) {
+    for (const element of elements) {
+      switch (element.type) {
+        case TYPE.argument:
+          params.set(element.value, { type: 'string' });
+          break;
+        case TYPE.date:
+          params.set(element.value, { type: 'Date' });
+          break;
+        case TYPE.literal:
+          break;
+        case TYPE.number:
+          params.set(element.value, { type: 'number' });
+          break;
+        case TYPE.plural:
+          params.set(element.value, { type: 'number' });
+          visitOptions(element.options);
+          break;
+        case TYPE.pound:
+          break;
+        case TYPE.select: {
+          const validOptions = Object.entries(element.options)
+            // We use empty {other ...} to satisfy smartling, but don't allow
+            // it in the app.
+            .filter(([key, { value }]) => key !== 'other' || value.length)
+            .map(([key]) => key);
+          params.set(element.value, { type: 'select', validOptions });
+          visitOptions(element.options);
+          break;
+        }
+        case TYPE.tag:
+          params.set(element.value, { type: 'jsx' });
+          visit(element.children);
+          break;
+        case TYPE.time:
+          params.set(element.value, { type: 'time' });
+          break;
+        default:
+          throw missingCaseError(element);
+      }
+    }
+  }
+
+  visit(parse(message));
+
+  for (const defaultRichTextElementName of defaultRichTextElementNames) {
+    params.delete(defaultRichTextElementName);
+  }
+
+  return params;
+}