moving i18n into taler util

1 files changed, 147 insertions, 0 deletions

diff --git a/packages/taler-util/src/i18n.ts b/packages/taler-util/src/i18n.ts
new file mode 100644
index 000000000..4253eb227
--- /dev/null
+++ b/packages/taler-util/src/i18n.ts
@@ -0,0 +1,147 @@
+// @ts-ignore: no type decl for this library
+import * as jedLib from "jed";
+import { Logger } from "./logging";
+
+const logger = new Logger("i18n/index.ts");
+
+export let jed: any = undefined;
+
+/**
+ * Set up jed library for internationalization,
+ * based on browser language settings.
+ */
+export function setupI18n(lang: string, strings: { [s: string]: any }): any {
+  lang = lang.replace("_", "-");
+
+  if (!strings[lang]) {
+    lang = "en-US";
+    logger.warn(`language ${lang} not found, defaulting to english`);
+  }
+  debugger
+  jed = new jedLib.Jed(strings[lang]);
+}
+
+/**
+ * Use different translations for testing.  Should not be used outside
+ * of test cases.
+ */
+export function internalSetStrings(langStrings: any): void {
+  jed = new jedLib.Jed(langStrings);
+}
+
+/**
+ * Convert template strings to a msgid
+ */
+function toI18nString(stringSeq: ReadonlyArray<string>): string {
+  let s = "";
+  for (let i = 0; i < stringSeq.length; i++) {
+    s += stringSeq[i];
+    if (i < stringSeq.length - 1) {
+      s += `%${i + 1}$s`;
+    }
+  }
+  return s;
+}
+
+/**
+ * Internationalize a string template with arbitrary serialized values.
+ */
+export function str(stringSeq: TemplateStringsArray, ...values: any[]): string {
+  const s = toI18nString(stringSeq);
+  const tr = jed
+    .translate(s)
+    .ifPlural(1, s)
+    .fetch(...values);
+  return tr;
+}
+
+/**
+ * Internationalize a string template without serializing
+ */
+export function translate(stringSeq: TemplateStringsArray, ...values: any[]): any[] {
+  const s = toI18nString(stringSeq);
+  if (!s) return []
+  const translation: string = jed.ngettext(s, s, 1);
+  return replacePlaceholderWithValues(translation, values)
+}
+
+/**
+ * Internationalize a string template without serializing
+ */
+export function Translate({ children, ...rest }: { children: any }): any {
+  const c = [].concat(children);
+  const s = stringifyArray(c);
+  if (!s) return []
+  const translation: string = jed.ngettext(s, s, 1);
+  return replacePlaceholderWithValues(translation, c)
+}
+
+/**
+ * Get an internationalized string (based on the globally set, current language)
+ * from a JSON object.  Fall back to the default language of the JSON object
+ * if no match exists.
+ */
+export function getJsonI18n<K extends string>(
+  obj: Record<K, string>,
+  key: K,
+): string {
+  return obj[key];
+}
+
+export function getTranslatedArray(array: Array<any>) {
+  const s = stringifyArray(array);
+  const translation: string = jed.ngettext(s, s, 1);
+  return replacePlaceholderWithValues(translation, array);
+}
+
+
+function replacePlaceholderWithValues(
+  translation: string,
+  childArray: Array<any>,
+): Array<any> {
+  const tr = translation.split(/%(\d+)\$s/);
+  // const childArray = toChildArray(children);
+  // Merge consecutive string children.
+  const placeholderChildren = [];
+  for (let i = 0; i < childArray.length; i++) {
+    const x = childArray[i];
+    if (x === undefined) {
+      continue;
+    } else if (typeof x === "string") {
+      continue;
+    } else {
+      placeholderChildren.push(x);
+    }
+  }
+  const result = [];
+  for (let i = 0; i < tr.length; i++) {
+    if (i % 2 == 0) {
+      // Text
+      result.push(tr[i]);
+    } else {
+      const childIdx = Number.parseInt(tr[i]) - 1;
+      result.push(placeholderChildren[childIdx]);
+    }
+  }
+  return result;
+}
+
+function stringifyArray(children: Array<any>): string {
+  let n = 1;
+  const ss = children.map((c) => {
+    if (typeof c === "string") {
+      return c;
+    }
+    return `%${n++}$s`;
+  });
+  const s = ss.join("").replace(/ +/g, " ").trim();
+  console.log("translation lookup", JSON.stringify(s));
+  return s;
+}
+
+export const i18n = {
+  str,
+  Translate,
+  translate
+}
+