1 files changed, 104 insertions, 0 deletions
diff --git a/shared/localization/src/i18n.ts b/shared/localization/src/i18n.ts
new file mode 100644
index 0000000..bcd5e28
--- /dev/null
+++ b/shared/localization/src/i18n.ts
@@ -0,0 +1,104 @@
+import Translator from './translator';
+import type {
+    Locale,
+    InterpolationOptions,
+    ILocaleJSON,
+    ITranslator,
+} from './types';
+import type { Logger } from '@amp/web-apps-logger';
+
+/** @internal */
+const formatOptions = (
+    options: InterpolationOptions | number,
+): InterpolationOptions =>
+    typeof options === 'number' ? { count: options } : options;
+
+/**
+ *
+ * Adapter class to expose expected LOC interface
+ * @category Localization
+ */
+export class I18N {
+    private readonly log: Logger;
+    private readonly locale: Locale;
+    private readonly translator: ITranslator;
+    private readonly keys: ILocaleJSON;
+    private readonly alwaysShowScreamers: boolean;
+
+    /**
+     * builds a new I18N class
+     * @param locale - the locale to use default:`'en-us'`
+     * @param translation - translation object default: `{}`
+     * @param alwaysShowScreamers - optional boolean that is set upstream
+     * by a FeatureKit feature flag. This makes it so the LOC keys themselves are
+     * printed to the DOM, rather than their translations, which is helpful for QA testing
+     */
+    constructor(
+        log: Logger,
+        locale: Locale = 'en-us',
+        translation: ILocaleJSON = {},
+        alwaysShowScreamers: boolean = false,
+    ) {
+        this.log = log;
+        this.locale = locale;
+        this.translator = new Translator(locale, translation, {
+            onMissingKeyFn: (key: string): string => {
+                log.warn('key missing:', key);
+                return `**${key}**`;
+            },
+            onMissingInterpolationFn: (key: string, interpolation: string) => {
+                log.warn(`key ${key} missing interpolation:`, interpolation);
+            },
+        });
+        this.keys = translation;
+        this.alwaysShowScreamers = alwaysShowScreamers;
+    }
+
+    get currentLocale(): Locale {
+        return this.locale;
+    }
+
+    get currentKeys(): ILocaleJSON {
+        return this.keys;
+    }
+
+    /**
+     * Gets non-interpolated string.
+     * @category Localization
+     * @param key key to lookup in the translation.json
+     * @returns an uninterpolated string value
+     */
+    getUninterpolatedString(key: string): string {
+        if (this.alwaysShowScreamers) {
+            return key;
+        } else {
+            return this.translator.getUninterpolatedString(key);
+        }
+    }
+
+    /**
+     * Method for fetching translation based on key.
+     *
+     * If alwaysShowScreamers is true, return the key itself for QA testing purposes
+     * (our app tends to call into this method within Svelte templates)
+     *
+     * @category Localization
+     * @param key key to lookup in the translation.json
+     * @param options options for translations
+     * @returns interpolated string
+     */
+    t = (key: string, options: number | InterpolationOptions = {}): string => {
+        if (this.alwaysShowScreamers) {
+            return key;
+        }
+
+        let internalOptions: InterpolationOptions = formatOptions(options);
+        if (typeof key !== 'string') {
+            this.log.warn('received non-string key:', key);
+            return '';
+        }
+        return this.translator.translate(key, internalOptions);
+    };
+}
+
+export default I18N;