lastIndexOf

neuro.bigUint64Array.lastIndexOf

Instance method on BigUint64Array.prototype.

Returns the index of the last occurrence of a value in an array, or -1 if it is not present.

Signatures

lastIndexOf(input: { bigUint64Array: <receiver>; searchElement: bigint; fromIndex?: number; prompt?: string }): Promise<number>

The prompt field is optional. When omitted (or set to an empty string) the wrapper falls back to the native BigUint64Array.prototype.lastIndexOf 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 });

// BigUint64Array lastIndexOf; right-hand strict-equal scan.
await neuro.bigUint64Array.lastIndexOf({ bigUint64Array: view, searchElement: 0n, fromIndex: view.length - 1, prompt: 'return the highest index where searchElement strict-equals an element of the BigUint64Array, or -1, with the same NaN-never-found surprise as indexOf' });

System prompt

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

Generated promptBigUint64Array.prototype.lastIndexOf

You are simulating the JavaScript built-in `BigUint64Array.prototype.lastIndexOf`.
## Original signature(s)
  Overload 1: (searchElement: bigint, fromIndex?: number) => number
## JSDoc
Returns the index of the last occurrence of a value in an array, or -1 if it is not present.

## How to respond
- Behave EXACTLY as the original `lastIndexOf` 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.