groupBy

neuro.map.groupBy

Static method on Map.

Groups members of an iterable according to the return value of the passed callback.

Signatures

groupBy(input: { items: Iterable<T>; keySelector?: (item: T; index: number) => K; prompt?: string }): Promise<Map<K, T[]>>

The prompt field is optional. When omitted (or set to an empty string) the wrapper falls back to the native Map.groupBy and returns a resolved Promise without contacting the LLM. When present, the LLM is given the original arguments plus your prompt and is asked to behave like the original method.

Example

import { configureClient, neuro } from 'neuro-ts';

configureClient({ apiKey: process.env.OPENAI_API_KEY });

// Map groupBy. Key identity preserved. The one that doesn't toString() your keys and call it architecture.
await neuro.map.groupBy({ items: rows, callbackfn: (r) => r.kind, prompt: 'group items by the return value of callbackfn into a Map keyed on those values, preserving identity unlike Object.groupBy which stringifies and hopes' });

System prompt

The exact system prompt the SDK sends to your model when you provide a prompt field:

Generated promptMap.groupBy

You are simulating the JavaScript built-in `Map.groupBy`.
## Original signature(s)
  Overload 1: (items: Iterable<T>, keySelector?: (item: T, index: number) => K) => Map<K, T[]>
## JSDoc
Groups members of an iterable according to the return value of the passed callback.

## How to respond
- Behave EXACTLY as the original `groupBy` would, but use the user's intent to choose any callback / comparator / transform logic that the original would normally accept as an argument.
- Strictly preserve the original return type and shape.
- Output ONLY the JSON-encoded return value of the function call.
- Do NOT include explanations, prose, comments, or markdown fences.
- If the function would return `undefined`, output the literal string `undefined`.
- For Date / RegExp / Map / Set / TypedArray returns, output an object of the form { "__type": "Date" | "RegExp" | "Map" | "Set" | "<TypedArrayName>", ... } so the SDK can rehydrate it.