PlanetScale Serverless Driver for JavaScript

A Fetch API-compatible PlanetScale database driver for serverless and edge compute platforms that require HTTP external connections, such as Cloudflare Workers or Vercel Edge Functions

Installation

npm install @planetscale/database

Usage

import { connect } from '@planetscale/database'

const config = {
  host: '<host>',
  username: '<user>',
  password: '<password>'
}

const conn = connect(config)
const results = await conn.execute('select 1 from dual where 1=?', [1])
console.log(results)

Database URL

A single database URL value can be used to configure the host, username, and password values.

import { connect } from '@planetscale/database'

const config = {
  url: process.env['DATABASE_URL'] || 'mysql://user:pass@host'
}

const conn = connect(config)

Connection factory

Use the Client connection factory class to create fresh connections for each transaction or web request handler.

import { Client } from '@planetscale/database'

const client = new Client({
  host: '<host>',
  username: '<user>',
  password: '<password>'
})

const conn = client.connection()
const results = await conn.execute('select 1 from dual')
console.log(results)

Transactions

Use the transaction function to safely perform database transactions. If any unhandled errors are thrown during execution of the transaction, the transaction will be rolled back.

The following example is based on the Slotted Counter Pattern.

import { connect } from '@planetscale/database'

const config = {
  host: '<host>',
  username: '<user>',
  password: '<password>'
}

const conn = connect(config)
const results = await conn.transaction(async (tx) => {
  const whenBranch = await tx.execute('INSERT INTO branches (database_id, name) VALUES (?, ?)', [42, "planetscale"])
  const whenCounter = await tx.execute('INSERT INTO slotted_counters(record_type, record_id, slot, count) VALUES (?, ?, RAND() * 100, 1) ON DUPLICATE KEY UPDATE count = count + 1', ['branch_count', 42])
  return [whenBranch, whenCounter]
})
console.log(results)

Custom fetch function

Node.js version 18 includes a built-in global fetch function. When using an older version of Node.js, you can provide a custom fetch function implementation. We recommend the undici package on which Node's built-in fetch is based.

import { connect } from '@planetscale/database'
import { fetch } from 'undici'

const config = {
  fetch,
  host: '<host>',
  username: '<user>',
  password: '<password>'
}

const conn = connect(config)
const results = await conn.execute('select 1 from dual')
console.log(results)

To leverage HTTP/2, you can use the fetch-h2 shim. fetch-h2 also supports Node.js 12+.

import { connect } from '@planetscale/database'
import { context } from 'fetch-h2'
const { fetch, disconnectAll } = context()

const config = {
  fetch,
  host: '<host>',
  username: '<user>',
  password: '<password>'
}

const conn = connect(config)
const results = await conn.execute('select 1 from dual')
console.log(results)
await disconnectAll()

Custom query parameter format function

Query replacement parameters identified with ? are replaced with escaped values. Named replacement parameters are supported with a colon prefix.

const results1 = await conn.execute('select 1 from dual where 1=?', [42])
const results2 = await conn.execute('select 1 from dual where 1=:id', { id: 42 })

Providing a custom format function overrides the built-in escaping with an external library, like sqlstring.

import { connect } from '@planetscale/database'
import SqlString from 'sqlstring'

const config = {
  format: SqlString.format,
  host: '<host>',
  username: '<user>',
  password: '<password>'
}

const conn = connect(config)
const results = await conn.execute('select 1 from dual where 1=?', [42])
console.log(results)

Custom type casting function

Column values are converted to their corresponding JavaScript data types. This can be customized by providing a cast function.

import { connect, cast } from '@planetscale/database'

function inflate(field, value) {
  if (field.type === 'INT64' || field.type === 'UINT64') {
    return BigInt(value)
  }
  return cast(field, value)
}

const config = {
  cast: inflate,
  host: '<host>',
  username: '<user>',
  password: '<password>'
}

const conn = connect(config)

You can also pass a custom cast function to execute. If present, this will override the cast function set by the connection:

const result = await conn.execute(
  'SELECT userId, SUM(balance) AS balance FROM UserBalanceItem GROUP BY userId',
  {},
  {
    cast: (field, value) => {
      if (field.name === 'balance') {
        return BigInt(value)
      }
      return cast(field, value)
    }
  }
)

Row return values

Rows can be returned as an object or an array of column values by passing an as option to execute.

const query = 'select 1 as one, 2 as two where 1=?'
const objects = conn.execute(query, [1], { as: 'object' })
// objects.rows => [{one: '1', two: '2'}]

const arrays = conn.execute(query, [1], { as: 'array' })
// arrays.rows => [['1', '2']]

Development

npm install
npm test

License

Distributed under the Apache 2.0 license. See LICENSE for details.