Added Cohere example [skip ci]

Author: ankane

README.md

@@ -32,6 +32,7 @@ And follow the instructions for your database library:
 Or check out some examples:
 
 - [Embeddings](examples/openai/example.js) with OpenAI
+- [Binary embeddings](examples/cohere/example.js) with Cohere
 - [Sentence embeddings](examples/transformers/example.js) with Transformers.js
 - [Hybrid search](examples/hybrid-search/example.js) with Transformers.js
 - [Recommendations](examples/disco/example.js) with Disco

examples/cohere/example.js

@@ -0,0 +1,42 @@
+import { CohereClient } from 'cohere-ai';
+import pg from 'pg';
+import pgvector from 'pgvector/pg';
+
+const client = new pg.Client({database: 'pgvector_example'});
+await client.connect();
+
+await client.query('CREATE EXTENSION IF NOT EXISTS vector');
+await pgvector.registerTypes(client);
+
+await client.query('DROP TABLE IF EXISTS documents');
+await client.query('CREATE TABLE documents (id bigserial PRIMARY KEY, content text, embedding bit(1024))');
+
+async function fetchEmbeddings(texts, inputType) {
+  const cohere = new CohereClient();
+  const response = await cohere.embed({
+    texts: texts,
+    model: 'embed-english-v3.0',
+    inputType: inputType,
+    embeddingTypes: ['ubinary']
+  });
+  return response.embeddings.ubinary.map((e) => e.map((v) => v.toString(2).padStart(8, '0')).join(''));
+}
+
+const input = [
+  'The dog is barking',
+  'The cat is purring',
+  'The bear is growling'
+];
+const embeddings = await fetchEmbeddings(input, 'search_document');
+for (let [i, content] of input.entries()) {
+  await client.query('INSERT INTO documents (content, embedding) VALUES ($1, $2)', [content, embeddings[i]]);
+}
+
+const query = 'forest';
+const queryEmbedding = (await fetchEmbeddings([query], 'search_query'))[0];
+const { rows } = await client.query('SELECT * FROM documents ORDER BY embedding <~> $1 LIMIT 5', [queryEmbedding]);
+for (let row of rows) {
+  console.log(row.content);
+}
+
+await client.end();

examples/cohere/package.json

@@ -0,0 +1,9 @@
+{
+    "private": true,
+    "type": "module",
+    "dependencies": {
+        "cohere-ai": "^7.10.6",
+        "pg": "^8.11.3",
+        "pgvector": "file:../.."
+    }
+}