Add helper methods for converting numeric/datetime/string array value…

…s to User Object attribute values

src/RolloutEvaluator.ts

@@ -9,6 +9,35 @@ import { errorToString, formatStringList, isArray, utf8Encode } from "./Utils";
 
 /** User Object. Contains user attributes which are used for evaluating targeting rules and percentage options. */
 export class User {
+  /**
+   * Converts the specified `Date` value to the format expected by datetime comparison operators (BEFORE/AFTER).
+   * @param date The `Date` value to convert.
+   * @returns The User Object attribute value in the expected format.
+  */
+  static attributeValueFromDate(date: Date): string {
+    const unixTimeSeconds = date.getTime() / 1000.0;
+    return unixTimeSeconds + "";
+  }
+
+  /**
+   * Converts the specified `number` value to the format expected by number comparison operators.
+   * @param number The `number` value to convert.
+   * @returns The User Object attribute value in the expected format.
+  */
+  static attributeValueFromNumber(number: number): string {
+    return number + "";
+  }
+
+  /**
+   * Converts the specified `string` items to the format expected by array comparison operators (ARRAY CONTAINS ANY OF/ARRAY NOT CONTAINS ANY OF).
+   * @param items The `string` items to convert.
+   * @returns The User Object attribute value in the expected format.
+  */
+  static attributeValueFromStringArray(...items: ReadonlyArray<string>): string {
+    // TODO: What to do when items contain non string items?
+    return JSON.stringify(items);
+  }
+
   constructor(
     /** The unique identifier of the user or session (e.g. email address, primary key, session ID, etc.) */
     public identifier: string,