[No QA] method to randomly generate 64 bit int as string

src/CONST.js

@@ -790,6 +790,8 @@ const CONST = {
         INVITE: 'invite',
         LEAVE_ROOM: 'leaveRoom',
     },
+    MAX_64BIT_LEFT_HALF: 9_223_372_036,
+    MAX_64BIT_RIGHT_HALF: 854_775_807,
     IOS_KEYBOARD_SPACE_OFFSET: -30,
 };
 

src/libs/NumberUtils.js

@@ -0,0 +1,32 @@
+import CONST from '../CONST';
+
+/**
+ * Generates a random positive 64 bit numeric string by randomly generating the left half and right half and concatenating them. Used to generate client-side ids.
+ * @returns {String} string representation of a randomly generated 64 bit signed integer
+ */
+/* eslint-disable no-unused-vars */
+function rand64() {
+    // Max 64-bit signed:
+    // 9,223,372,036,854,775,807
+    // The left part of the max 64-bit number *+1* because we're flooring it
+    const left = Math.floor(Math.random() * (CONST.MAX_64BIT_LEFT_HALF + 1));
+
+    // The right part of the max 64-bit number *+1* for the same reason
+    let right;
+
+    // If the top is any number but the highest one, we can actually have any value for the rest
+    if (left !== CONST.MAX_64BIT_LEFT_HALF) {
+        right = Math.floor(Math.random() * 1_000_000_000);
+    } else {
+        right = Math.floor(Math.random() * (CONST.MAX_64BIT_RIGHT_HALF + 1));
+    }
+
+    // Pad the right with zeros
+    const rightString = right.toString().padStart(9, '0');
+
+    return left + rightString;
+}
+
+module.exports = {
+    rand64,
+};

tests/unit/NumberUtilsTest.js

@@ -0,0 +1,13 @@
+const NumberUtils = require('../../src/libs/NumberUtils');
+
+describe('libs/NumberUtils', () => {
+    it('should generate a random 64-bit numeric string', () => {
+        const id = NumberUtils.rand64();
+        expect(typeof id).toBe('string');
+        // eslint-disable-next-line no-undef
+        expect(BigInt(id)).toBeLessThanOrEqual(BigInt(9223372036854775807));
+        // eslint-disable-next-line no-undef
+        expect(BigInt(id)).toBeGreaterThanOrEqual(0);
+    });
+});
+