faiss-napi/examples/index.js

JavaScript NAPI bindings for faiss

const { IndexFlatL2, Index, IndexFlatIP, MetricType } = require('../');

const dimension = 2;
const index = new IndexFlatL2(dimension);

console.log(index.dims); // 2
console.log(index.isTrained); // true
console.log(index.ntotal); // 0

// inserting data into index.
index.add([1, 0]);
index.add([1, 2]);
index.add([1, 3]);
index.add([1, 1]);

console.log(index.ntotal); // 4

const k = 4;
const results = index.search([1, 0], k);
console.log(results.labels); // [ 0, 3, 1, 2 ]
console.log(results.distances); // [ 0, 1, 4, 9 ]

// Save index
const fname = 'faiss.index';
index.write(fname);

// Load saved index
const index_loaded = IndexFlatL2.read(fname);
console.log(index_loaded.dims); //2
console.log(index_loaded.ntotal); //4
const results1 = index_loaded.search([1, 1], 4);
console.log(results1.labels); // [ 3, 0, 1, 2 ]
console.log(results1.distances); // [ 0, 1, 1, 4 ]

// Merge index
const newIndex = new IndexFlatL2(dimension);
newIndex.mergeFrom(index);
console.log(newIndex.ntotal); // 4

// Remove items
console.log(newIndex.search([1, 2], 1)); // { distances: [ 0 ], labels: [ 1 ] }
const removedCount = newIndex.removeIds([0]);
console.log(removedCount); // 1
console.log(newIndex.ntotal); // 3
console.log(newIndex.search([1, 2], 1)); // { distances: [ 0 ], labels: [ 0 ] }

// IndexFlatIP
const ipIndex = new IndexFlatIP(2);
ipIndex.add([1, 0]);

// Serialize an index
const index_buf = newIndex.toBuffer();
const deserializedIndex = Index.fromBuffer(index_buf);
console.log(deserializedIndex.ntotal); // 3

// Factory index
const hnswIndex = Index.fromFactory(2, 'HNSW,Flat', MetricType.METRIC_INNER_PRODUCT);
const x = [1, 0, 0, 1];
hnswIndex.train(x);
hnswIndex.add(x);