clickhouse-js-node-coding

✓ Official★ 321

by clickhouse · part of clickhouse/clickhouse-js

Write idiomatic application code with the ClickHouse Node.js client (`@clickhouse/client`). Use this skill whenever a user is *building* against the Node.js client — configuring the client, pinging, inserting rows in JSON or raw formats, selecting and parsing results, binding query parameters, managing sessions and temporary tables, working with data types or customizing JSON parsing. Do NOT use for browser/Web client code.

🔥🔥🔥✓ VerifiedFreeQuick setup

#database #cloud #devops #git #security #memory

🧰 Not standalone. This skill ships with clickhouse/clickhouse-js and only works together with that tool — install the tool first, then add this skill.

This is the playbook your agent receives when the skill activates — you don't need to read it to use the skill, but it's here to audit before installing.

ClickHouse Node.js Client — Coding

Reference: https://clickhouse.com/docs/integrations/javascript

⚠️ Node.js runtime only. This skill covers the @clickhouse/client package running in a Node.js runtime exclusively — including Next.js Node runtime API routes, React Server Components, Server Actions, and standard Node.js processes. Do not apply this skill to browser client components, Web Workers, Next.js Edge runtime, Cloudflare Workers, or any usage of @clickhouse/client-web. For browser/edge environments, the correct package is @clickhouse/client-web.

Task Index

Identify the user's task and read the matching reference file.

Task	Triggers / symptoms	Reference file
Configure / connect the client	Building a `createClient` call, URL parameters, `clickhouse_settings`, default format, custom HTTP headers	`reference/client-configuration.md`
Compress requests / responses	`compression`, gzip vs `zstd`, `{ codec }` option shape, Node version requirements, web limitations	`reference/compression.md`
Ping the server	Health checks, readiness probes, "is ClickHouse up?"	`reference/ping.md`
Choose an insert format	"Which format should I use to insert?", JSON vs raw, `JSONEachRow` vs `JSON` vs `JSONObjectEachRow`	`reference/insert-formats.md`
Insert into a subset of columns / different database	`insert({ columns })`, excluding columns, ephemeral columns, cross-DB inserts	`reference/insert-columns.md`
Insert values, expressions, dates, decimals	`INSERT … VALUES` with SQL functions, `Date`/`DateTime` from JS, `Decimal` precision, `INSERT … SELECT`; inserting a UUID into a `UInt128` column is tricky — use when the user is writing code that stores a UUID as `UInt128`	`reference/insert-values.md`
Async inserts (server-side batching)	`async_insert=1`, fire-and-forget vs wait-for-ack	`reference/async-insert.md`
Select and parse results	`JSONEachRow` reads, `JSON` with metadata, picking a select format	`reference/select-formats.md`
Parameterize queries	Binding values, special characters / escaping, "SQL injection?", `{name: Type}` syntax	`reference/query-parameters.md`
Sessions & temporary tables	`session_id`, `CREATE TEMPORARY TABLE`, per-session `SET` commands	`reference/sessions.md`
Modern data types	`Dynamic`, `Variant`, `JSON` (object), `Time`, `Time64`, `QBit` (vector search)	`reference/data-types.md`
Custom JSON parse/stringify	Plug in `JSONBig` / `safe-stable-stringify` / a `BigInt`-aware serializer	`reference/custom-json.md`

Conventions used in answers

Always show import { createClient } from '@clickhouse/client' (Node, never Web).
Always await client.close() at the end of self-contained snippets; in long-running services, close on graceful shutdown.
For inserts, prefer format: 'JSONEachRow' and values: [...] unless the user's scenario requires otherwise.
For selects, prefer await (await client.query({...})).json<RowType>() for small / medium result sets; for bigger results suggest streaming.
When showing parameter binding, use ClickHouse's native {name: Type} syntax — never $1, ?, or :name.
For DDL inside a cluster or behind a load balancer, set clickhouse_settings: { wait_end_of_query: 1 } on the command() call so the server only acknowledges after the change is applied. See https://clickhouse.com/docs/en/interfaces/http/#response-buffering.

Out of scope

This skill covers day-to-day coding against @clickhouse/client (Node). The following topics are intentionally not covered here:

Errors, hangs, type mismatches, proxy pathname surprises, log silence, socket hang-ups, ECONNRESET → use the clickhouse-js-node-troubleshooting skill.
Streaming, Parquet, file streams, server-side bulk moves, progress streaming, async-insert throughput tuning — see examples/node/performance/.
TLS, RBAC / read-only users, deeper SQL-injection guidance — see examples/node/security/.
CREATE TABLE patterns, deployment-shaped connection strings, replication / sharding choices — see examples/node/schema-and-deployments/.
Browser, Web Worker, Next.js Edge, Cloudflare Workers — use @clickhouse/client-web and see examples/web/.

Still Stuck?

examples/node/coding/ — the runnable corpus this skill is built on.
ClickHouse JS client docs
ClickHouse supported formats
ClickHouse data types

Copy & paste — that's it

npx skills add clickhouse/clickhouse-js --skill "clickhouse-js-node-coding" --full-depth

Run this in your project — your agent picks the skill up automatically.

How to Use This Skill

Match the user's intent to a row in the Task Index below and read the corresponding reference file before writing code. After reading it, scan any Answer checklist in that reference and make sure the final answer covers each relevant item; those checklists capture details users usually need but are easy to omit in short answers.
Always import from @clickhouse/client (never @clickhouse/client-web) and create a client with createClient({ url }) or rely on supported defaults when appropriate. Close it with await client.close() preferably when it's no longer needed or during graceful shutdown for global resources.
Prefer JSONEachRow for typical row inserts/selects unless the user has already chosen another format or is streaming raw bytes (CSV / TSV / Parquet — see examples/node/performance/). Note on clickhouse_settings: settings passed to createClient are defaults for every request; they can be overridden per-call by passing clickhouse_settings directly to insert(), query(), or command(). Always mention this when the user configures settings at the client level.
Always use query_params for user-supplied values — never template- literal-interpolate them into SQL. See reference/query-parameters.md. When answering a parameter-binding question, your response must explicitly name template-literal interpolation as a "SQL injection risk" — even when the user only asked about syntax and did not raise security. The literal phrase "SQL injection" needs to appear; this is the most common mistake from PostgreSQL/MySQL users and the security framing is part of the correct answer, not an optional aside.
Pick the right method for the job:
- client.insert() — write rows.
- client.query() + resultSet.json() / .text() / .stream() — read rows that return data.
- client.command() — DDL and other statements that don't return rows (CREATE, DROP, TRUNCATE, ALTER, SET in a session, etc.).
- client.exec() — when you need the raw response stream of an arbitrary statement (rare in coding scenarios).
- client.ping() — health check; returns { success, error? }, never throws on connection failure.
Note version constraints when relevant. Examples:
- pathname config option: client >= 1.0.0.
- BigInt values in query_params: client >= 1.15.0.
- TupleParam and JS Map in query_params: client >= 1.9.0.
- Configurable json.parse / json.stringify: client >= 1.14.0.
- Time / Time64 data types: ClickHouse server >= 25.6.
- QBit data type: ClickHouse server >= 25.10 (GA on 26.x).
- Dynamic / Variant / new JSON types: ClickHouse server >= 24.1 / 24.5 / 24.8 (no longer experimental since 25.3).