Package Exports

substreams
substreams/dist/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (substreams) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

`Substreams` Javascript consumer

License

Substream Javascript consumer library using Node.js Event emitters.

Install

Using NPM:

npm install --save substreams

or using Yarn:

yarn add substreams

Requirements

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");

    // first block received
    substreams.on("start", (cursor, clock) => {
        console.log({status: "start", cursor, clock});
    });

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

    // end of stream
    substreams.on("end", (cursor, clock) => {
        console.log({status: "end", cursor, clock});
    });

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

Tests

$ npm ci
$ npm test

substreams