---
sourceDocument: Brazil Build or modify applications
sourceDocumentLink: https://www.servicenow.com/docs/r/application-development

 Release :

    - brazil

ft:locale :

    - en-US

ft:publication_title :

    - Brazil Build or modify applications

ft:clusterId :

    - cadev

bundleId :

    - cadev

workflow :

    - Development, Data, and Analytics


---

# Configure type checking

# Configure type checking {#ariaid-title1}

Release version: Brazil  
Updated October 26, 2026  
![](https://www.servicenow.com/docs/portal-asset/ico-clock) 1 minute to read  
Configure type checking for a component and JavaScript-only project.

## Before you begin

* The ui-component extension must be installed. See [Install the UI component CLI extension](https://www.servicenow.com/docs/FGXeLXFsYDtdByOIiPN2tQ "Install the UI component extension to develop Next Experience UI Framework components with the ServiceNow CLI.").
* The Next Experience UI component project must exist.
Role required: admin

## About this task

Type checking is enabled by default for projects that use both TypeScript and JavaScript. For a JavaScript-only project, type checking requires a tsconfig.json file with type checking enabled.

## Procedure

1. Set the type checking property in the now-cli.json file at the root of the project.  
   Note:  
   If you provide both the CLI option and typescript.typeCheck, the CLI option takes precedence.  

       {
                               "typescript": {
                               "typeCheck": true
                               }
                               }

2. Create a tsconfig.json file for a JavaScript-only project.
3. Insert the file at the root of the project or monorepo with the following compiler options.  
   Note:  
   The extension provides a default tsconfig.json file. A tsconfig.json file that you define overrides the default.

       {
                               "compilerOptions": {
                               "allowJs": true,
                               "checkJs": true
                               }
                               }

## Result

The extension type checks the project files according to the settings that you configured.