v0.3.0

New Features

• set host as default (optional) uses StreamingFast ETH mainnet
• set default startBlock=0
• improve stopBlock handling (allows "+100" )
• replace example.js using ETH using Subtivity substream
• get authentication token using StreamingFast issue endpoint

Substreams Javascript consumer

Substream Javascript consumer library using Node.js Event emitters.

Install

Using NPM:

npm install --save substreams

or using Yarn:

yarn add substreams

Requirements

• Node.js (LTS or Current)
• Buf - Protocol Buffers

Endpoints

• https://github.com/pinax-network/endpoints

Quickstart

const { Substreams, download } = require("substreams");

// User input
const spkg = "https://github.com/pinax-network/subtivity-substreams/releases/download/v0.1.0/subtivity-ethereum-v0.1.0.spkg";
const outputModule = "map_block_stats";
const startBlockNum = "300000";
const stopBlockNum = "+10";

// Initialize Substreams
const substreams = new Substreams(outputModule, {
    startBlockNum,
    stopBlockNum,
    authorization: process.env.STREAMINGFAST_KEY // or SUBSTREAMS_API_TOKEN
});

(async () => {
    // download Substream from IPFS
    const {modules, registry} = await download(spkg);

    // Find Protobuf message types from registry
    const BlockStats = registry.findMessage("subtivity.v1.BlockStats");
    if ( !BlockStats) throw new Error("Could not find BlockStats message type");

    substreams.on("mapOutput", output => {
        const decoded = BlockStats.fromBinary(output.data.mapOutput.value);
        console.log(decoded);
    });

    // start streaming Substream
    await substreams.start(modules);

    // end of Substream
    console.log("done");
    process.exit();
})();

Tests

$ npm ci
$ npm test