ko

library6.6.7jsnpmunverified

Ko is a CLI tool for building and linting React applications. It uses webpack v5 and esbuild under the hood, providing a zero-config setup with customizable options. Version 6.6.7 is the latest stable release, with active development and a monthly release cadence. Key differentiators include built-in support for TypeScript, Sass/SCSS, Babel, and popular linting tools, as well as integration with the DTStack ecosystem. It is designed to simplify the build process for React projects, similar to Create React App but with more flexibility for advanced configurations.

devops

npm install ko

github ↗package ↗

INSTALL

IMPORT

SIG · KO

devopsjavascriptv6.6.7

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

✓ import ko from 'ko'

✗ const ko = require('ko')

Default import is used for the CLI entry point; for programmatic usage, ko may export an object with builder/linter functions.

build

✓ import { build } from 'ko'

✗ import build from 'ko'

Named export for build function available since v6.0.

lint

✓ import { lint } from 'ko'

✗ import { koLint } from 'ko'

Correct named export is 'lint', not 'koLint'.

type CheckConfig

✓ import type { Config } from 'ko'

✗ import { Config } from 'ko'

TypeScript type export; use import type to avoid runtime errors.

Shows how to create a new project with ko, start dev server, build for production, and run linting.

// Initialize a new ko project npx ko init my-app cd my-app // Start development server npx ko dev // Build for production npx ko build // Lint source code npx ko lint

ko --version

Debug

Known issues

breakingko v6.0.0 drops support for webpack v4; projects using webpack v4 must upgrade.

fix

Update webpack to v5 or use ko v5.x.

affects: >=6.0.0 <6.0.0

deprecatedko v6.3.0 deprecates 'analyze' command in favor of 'build --analyze'.

fix

Replace `ko analyze` with `ko build --analyze`.

affects: >=6.3.0

gotchako uses esbuild for dev server; certain webpack loaders may not work with esbuild and will cause silent failures.

fix

Disable esbuild in ko.config.js by setting 'builder: "webpack"'.

affects: >=6.0.0

gotchako enforces 'import type' for TypeScript type imports; using regular import may result in runtime errors in production builds.

fix

Use `import type { ... }` for type-only imports.

affects: >=6.5.0

gotchako's default Babel config includes @babel/preset-env which may cause issues with older Node versions.

fix

Set Node engine or configure Babel targets in ko.config.js.

affects: >=6.0.0

gotchako caches build artifacts in .ko-cache; clearing this cache can resolve unexpected build errors.

fix

Run `npx ko clean` to clear cache.

affects: >=6.0.0

Errors

Common errors & fixes

ModuleNotFoundError: Module not found: Error: Can't resolve 'ko'

ko is not installed or not in node_modules.

fix

Run `npm install ko --save-dev`.

Error: ko.config.js is not a valid configuration file

Syntax error or missing export in config file.

fix

Ensure ko.config.js exports a valid configuration object: module.exports = { ... }.

TypeError: Cannot read property 'build' of undefined

Importing from ko incorrectly.

fix

Use `import { build } from 'ko'` or `import ko from 'ko'` and access ko.build.

Error: [BABEL] Cannot find module '@babel/core'

Missing Babel dependency.

fix

Run `npm install @babel/core @babel/preset-env --save-dev`.

Upgrade

Version history

6.6.7latest on npm

Audit

Dependencies

webpackrequiredCore bundler used for production builds

esbuildoptionalUsed for dev builds and fast compilation

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/DTStack/ko ↗

packagehttps://www.npmjs.com/package/ko ↗