---
title: Javascript-SDK - [3.1.0-beta1] - March 6th, 2019
slug: feature-experimentation/release-notes/javascript-sdk-3-1-0-beta1-march-6th-2019
docTags: 
createdAt: 2026-07-20T15:45:44.418Z
---

\## \[3.1.0-beta1] - March 6th, 2019

\### Changed

\- New APIs for setting \`logger\` and \`logLevel\` on the optimizelySDK singleton (\[#232]\([https://github.com/optimizely/javascript-sdk/pull/232](https://github.com/optimizely/javascript-sdk/pull/232)))
\- \`logger\` and \`logLevel\` are now set globally for all instances of Optimizely. If you were passing
different loggers to individual instances of Optimizely, logging behavior may now be different.

\#### Setting a ConsoleLogger

\`\`\`js
var optimizelySDK = require('@optimizely/optimizely-sdk')

// logger and logLevel are now set on the optimizelySDK singleton
optimizelySDK.setLogger(optimizelySDK.logging.createLogger())

// valid levels: 'DEBUG', 'INFO', 'WARN', 'ERROR'
optimizelySDK.setLogLevel('WARN')
// enums can also be used
optimizelySDK.setLogLevel(optimizely.enums.LOG\_LEVEL.ERROR)
\`\`\`

\#### Disable logging

\`\`\`js
var optimizelySDK = require('@optimizely/optimizely-sdk')

optimizelySDK.setLogger(null)
\`\`\`

[https://github.com/optimizely/javascript-sdk/releases/tag/v3.1.0-beta1](https://github.com/optimizely/javascript-sdk/releases/tag/v3.1.0-beta1)