PlanetScale serverless JavaScript driver for Vitess/MySQL

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

Tip

Connecting to a PlanetScale Postgres database? We support the Neon serverless driver, read the documentation to connect.

Installation

npm install @planetscale/database

Usage

import{connect}from'@planetscale/database'constconfig={host: '<host>',username: '<user>',password: '<password>'}constconn=connect(config)constresults=awaitconn.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'constconfig={url: process.env['DATABASE_URL']||'mysql://user:pass@host'}constconn=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'constclient=newClient({host: '<host>',username: '<user>',password: '<password>'})constconn=client.connection()constresults=awaitconn.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'constconfig={host: '<host>',username: '<user>',password: '<password>'}constconn=connect(config)constresults=awaitconn.transaction(async(tx)=>{constwhenBranch=awaittx.execute('INSERT INTO branches (database_id, name) VALUES (?, ?)',[42,"planetscale"])constwhenCounter=awaittx.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'constconfig={
fetch,host: '<host>',username: '<user>',password: '<password>'}constconn=connect(config)constresults=awaitconn.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()constconfig={
fetch,host: '<host>',username: '<user>',password: '<password>'}constconn=connect(config)constresults=awaitconn.execute('select 1 from dual')console.log(results)awaitdisconnectAll()

Custom query parameter format function

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

constresults1=awaitconn.execute('select 1 from dual where 1=?',[42])constresults2=awaitconn.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'importSqlStringfrom'sqlstring'constconfig={format: SqlString.format,host: '<host>',username: '<user>',password: '<password>'}constconn=connect(config)constresults=awaitconn.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'functioninflate(field,value){if(field.type==='INT64'||field.type==='UINT64'){returnBigInt(value)}returncast(field,value)}constconfig={cast: inflate,host: '<host>',username: '<user>',password: '<password>'}constconn=connect(config)

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

constresult=awaitconn.execute('SELECT userId, SUM(balance) AS balance FROM UserBalanceItem GROUP BY userId',{},{cast: (field,value)=>{if(field.name==='balance'){returnBigInt(value)}returncast(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.

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

Development

npm install
npm test

Need help?

Get help from the PlanetScale support team, or join our community on Discord or GitHub discussion board to see how others are using PlanetScale.

License

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