Allow users to pass customField to /rerank endpoint (#303)

## Problem

The current implementation of `/rerank` in the TS client does not
(correctly) allow users to pass a custom field upon which to rerank.

## Solution

Allow custom fields!

Please reference this PR to account for all expected functionality:
https://github.com/pinecone-io/python-plugin-inference/pull/21/files

## Type of Change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] This change requires a documentation update
- [ ] Infrastructure change (CI configs, etc)
- [ ] Non-code change (docs, etc)
- [ ] None of the above: (explain here)

## Test Plan

CI passes + reviewer xreferences PR above w/functionality introduced in
this PR.

---
- To see the specific tasks where the Asana app for GitHub is being
used, see below:
  - https://app.asana.com/0/0/1208523729730914

---------

Co-authored-by: Jesse Seldess <[email protected]>

README.md

@@ -1104,20 +1104,20 @@ import { Pinecone } from '@pinecone-database/pinecone';
 const pc = new Pinecone();
 const rerankingModel = 'bge-reranker-v2-m3';
 const myQuery = 'What are some good Turkey dishes for Thanksgiving?';
-const myDocuments = [
-  { text: 'I love turkey sandwiches with pastrami' },
-  {
-    text: 'A lemon brined Turkey with apple sausage stuffing is a classic Thanksgiving main',
-  },
-  { text: 'My favorite Thanksgiving dish is pumpkin pie' },
-  { text: 'Turkey is a great source of protein' },
+
+// Option 1: Documents as an array of strings
+const myDocsStrings = [
+  'I love turkey sandwiches with pastrami',
+  'A lemon brined Turkey with apple sausage stuffing is a classic Thanksgiving main',
+  'My favorite Thanksgiving dish is pumpkin pie',
+  'Turkey is a great source of protein',
 ];
 
-// >>> Sample without passing an `options` object:
+// Option 1 response
 const response = await pc.inference.rerank(
   rerankingModel,
   myQuery,
-  myDocuments
+  myDocsStrings
 );
 console.log(response);
 // {
@@ -1131,15 +1131,43 @@ console.log(response);
 // usage: { rerankUnits: 1 }
 // }
 
-// >>> Sample with an `options` object:
+// Option 2: Documents as an array of objects
+const myDocsObjs = [
+  {
+    title: 'Turkey Sandwiches',
+    body: 'I love turkey sandwiches with pastrami',
+  },
+  {
+    title: 'Lemon Turkey',
+    body: 'A lemon brined Turkey with apple sausage stuffing is a classic Thanksgiving main',
+  },
+  {
+    title: 'Thanksgiving',
+    body: 'My favorite Thanksgiving dish is pumpkin pie',
+  },
+  {
+    title: 'Protein Sources',
+    body: 'Turkey is a great source of protein',
+  },
+];
+
+// Option 2: Options object declaring which custom key to rerank on
+// Note: If no custom key is passed via `rankFields`, each doc must contain a `text` key, and that will act as the default)
 const rerankOptions = {
   topN: 3,
   returnDocuments: false,
+  rankFields: ['body'],
+  parameters: {
+    inputType: 'passage',
+    truncate: 'END',
+  },
 };
+
+// Option 2 response
 const response = await pc.inference.rerank(
   rerankingModel,
   myQuery,
-  myDocuments,
+  myDocsObjs,
   rerankOptions
 );
 console.log(response);

src/inference/__tests__/embed.test.ts

@@ -0,0 +1,42 @@
+import { Inference } from '../inference';
+import type { PineconeConfiguration } from '../../data';
+import { inferenceOperationsBuilder } from '../inferenceOperationsBuilder';
+
+let inference: Inference;
+
+beforeAll(() => {
+  const config: PineconeConfiguration = { apiKey: 'test-api-key' };
+  const infApi = inferenceOperationsBuilder(config);
+  inference = new Inference(infApi);
+});
+
+describe('Inference Class: _formatInputs', () => {
+  test('Should format inputs correctly', () => {
+    const inputs = ['input1', 'input2'];
+    const expected = [{ text: 'input1' }, { text: 'input2' }];
+    const result = inference._formatInputs(inputs);
+    expect(result).toEqual(expected);
+  });
+});
+
+describe('Inference Class: embed', () => {
+  test('Should throw error if response is missing required fields', async () => {
+    const model = 'test-model';
+    const inputs = ['input1', 'input2'];
+    const params = { inputType: 'text', truncate: 'END' };
+
+    const mockedIncorrectResponse = { model: 'test-model' };
+    const expectedError = Error(
+      'Response from Inference API is missing required fields'
+    );
+    const embed = jest.spyOn(inference._inferenceApi, 'embed');
+    // @ts-ignore
+    embed.mockResolvedValue(mockedIncorrectResponse);
+
+    try {
+      await inference.embed(model, inputs, params);
+    } catch (error) {
+      expect(error).toEqual(expectedError);
+    }
+  });
+});