A Typescript wrapper for Index Supply's API.
This package is available on NPM.
npm i @indexsupply/indexsupply.js
Make a one-time query to get historical data:
import { query } from "@indexsupply/indexsupply.js";
const { blockNumber, result } = await query({
apiKey: "face",
chainId: 8453,
query: 'select "from", "to", value from transfer limit 1',
eventSignatures: ['Transfer(address indexed from, address indexed to, uint256 value)'],
formatRow: ([from, to, value]) => ({
from: from as Address,
to: to as Address,
value: BigInt(value),
}),
})
console.log(`Block ${blockNumber}:`, result)Subscribe to new data as it arrives:
import { queryLive } from "@indexsupply/indexsupply.js";
const q = queryLive({
apiKey: "face",
chainId: 8453,
startBlock: async () => 1234567n,
query: 'select "from", "to", value from transfer limit 1',
eventSignatures: ['Transfer(address indexed from, address indexed to, uint256 value)'],
formatRow: ([from, to, value]) => ({
from: from as Address,
to: to as Address,
value: BigInt(value),
}),
})
for await (const { blockNumber, result } of q) {
console.log(`New data at block ${blockNumber}:`, result)
}queryLive will call startBlock each time a new connection to the server is established. If the connection is restarted
then queryLive will automatically restablish the connection and will call startBlock to ensure we resume at the correct
block height.
A common pattern for startBlock is to use your database to figure out the last block you've processed. For example:
const liveQuery = queryLive({
startBlock: async () => {
const rows = await pg.query("select max(block_num) block_num from my_table");
return BigInt(rows[0].block_num);
},
...
});
for await (const { blockNumber, result } of liveQuery) {
await pg.query("insert into my_table(block_num, ...) values (blockNumber, ...)");
}See the examples/save-to-postgres source for a complete example.
See this page for a working demonstration.
<html>
<head>
<script src="https://static.indexsupply.net/indexsupply.js" type="module"></script>
</head>
<script type="module">
import { query } from "https://static.indexsupply.net/indexsupply.js";
const { blockNumber, result } = await query({
chainId: 8453n,
eventSignatures: [],
query: "select block_num from logs limit 1",
});
document.querySelector("body pre").textContent = JSON.stringify({ blockNumber, result });
</script>
<body>
<pre></pre>
</body>
</html>% node --version
v22.12.0
% npm run example
> @indexsupply/indexsupply.js@0.0.7 example
> npx tsx examples/live.ts
{
tx: '0x3f6664da84f4cc2f3bbfd5b9968ea0c06c4d89b682c920ee240f13d9824cbabf',
block: 23815441n
}