Aggregate emoji reactions by name

Aggregate reactions by normalized emoji name, count unique users once, and retain deterministic first-seen group order.

EasyJavaScript Product Algorithms

30 min0% acceptance

Description

Aggregate reactions by normalized emoji name, count unique users once, and retain deterministic first-seen group order. Implement the learner-facing contract completely and satisfy every observable requirement without relying on hidden infrastructure.

Requirements

Export aggregateEmojiReactions from src/App.js.
Trim names and remove one surrounding colon pair before grouping.
Count each nonempty userId at most once within an emoji group.
Order groups by the first valid occurrence of each normalized name.
Return each group's unique userIds in ascending lexical order.
Return an observably equivalent result for equivalent inputs without reading time, randomness, network, storage, or DOM globals.
Do not mutate input objects, arrays, nested records, or values retained in the returned result.

Duplicate reaction

Input

Ada reacts :shipit: twice

Expected output

shipit count remains one for Ada

Explanation

Trim names and remove one surrounding colon pair before grouping.

Mixed names

Input

thumbsup then heart then :thumbsup:

Expected output

Groups stay thumbsup, heart

Explanation

Count each nonempty userId at most once within an emoji group.

Constraints

Implement a pure synchronous function with no external side effects
Treat every input collection and nested record as read-only
Return JSON-compatible data except where the declared TypeScript API explicitly uses bigint

Hints

Hint 1

Start with the normalizes-emoji-name behavior and make its observable result deterministic.

Hint 2

Model counts-unique-users independently before combining it with the remaining states.

Hint 3

Verify the boundary described by sorts-user-ids without changing caller-owned input.

JavaScriptemojiaggregation