x)
- [ ] new
- [x] build
- [ ] serve
- [ ] test
- [ ] e2e
- [ ] generate
- [ ] add
- [x] update
- [ ] lint
- [ ] xi18n
- [ ] run
- [ ] config
- [ ] help
- [ ] version
- [ ] doc
 Yes, the previous version in which this bug was not present was: ....
A clear and concise description of the problem...
After ng update @angular/cli from Anguar CLI v7.3.6, ng build command throws such error. 
I didn't get a repro yet. In my situation, the project has some caniuse-related dependencies;
Diff of yarn.lock is here;
Before
caniuse-lite@^1.0.30000929, caniuse-lite@^1.0.30000947, caniuse-lite@^1.0.30000955:
  version "1.0.30000955"
  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30000955.tgz#360fdb9a1e41d6dd996130411334e44a39e4446d"
  integrity sha512-6AwmIKgqCYfDWWadRkAuZSHMQP4Mmy96xAXEdRBlN/luQhlRYOKgwOlZ9plpCOsVbBuqbTmGqDK3JUM/nlr8CA==
caniuse-lite@^1.0.30000957, caniuse-lite@^1.0.30000960:
  version "1.0.30000962"
  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30000962.tgz#6c10c3ab304b89bea905e66adf98c0905088ee44"
  integrity sha512-WXYsW38HK+6eaj5IZR16Rn91TGhU3OhbwjKZvJ4HN/XBIABLKfbij9Mnd3pM0VEwZSlltWjoWg3I8FQ0DGgNOA==
After ng update
caniuse-lite@^1.0.0:
  version "1.0.30000971"
  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30000971.tgz#d1000e4546486a6977756547352bc96a4cfd2b13"
  integrity sha512-TQFYFhRS0O5rdsmSbF1Wn+16latXYsQJat66f7S7lizXW1PVpWJeZw9wqqVLIjuxDRz7s7xRUj13QCfd8hKn6g==
caniuse-lite@^1.0.30000929, caniuse-lite@^1.0.30000947, caniuse-lite@^1.0.30000955:
  version "1.0.30000955"
  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30000955.tgz#360fdb9a1e41d6dd996130411334e44a39e4446d"
  integrity sha512-6AwmIKgqCYfDWWadRkAuZSHMQP4Mmy96xAXEdRBlN/luQhlRYOKgwOlZ9plpCOsVbBuqbTmGqDK3JUM/nlr8CA==
caniuse-lite@^1.0.30000957, caniuse-lite@^1.0.30000960:
  version "1.0.30000962"
  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30000962.tgz#6c10c3ab304b89bea905e66adf98c0905088ee44"
  integrity sha512-WXYsW38HK+6eaj5IZR16Rn91TGhU3OhbwjKZvJ4HN/XBIABLKfbij9Mnd3pM0VEwZSlltWjoWg3I8FQ0DGgNOA==
$ ng build 
Unknown browser kaios
BrowserslistError: Unknown browser kaios
    at checkName (/Users/laco/Works/xxxxxx/node_modules/browserslist/index.js:171:20)
    at Function.select (/Users/laco/Works/xxxxxx/node_modules/browserslist/index.js:881:18)
    at /Users/laco/Works/xxxxxx/node_modules/browserslist/index.js:215:33
    at Array.reduce ()
    at resolve (/Users/laco/Works/xxxxxx/node_modules/browserslist/index.js:197:18)
    at browserslist (/Users/laco/Works/xxxxxx/node_modules/browserslist/index.js:317:16)
    at Object.isSupported (/Users/laco/Works/xxxxxx/node_modules/caniuse-api/dist/index.js:62:37)
    at isEs5SupportNeeded (/Users/laco/Works/xxxxxx/node_modules/@angular-devkit/build-angular/src/utils/differential-loading.js:22:21)
    at Object.isDifferentialLoadingNeeded (/Users/laco/Works/xxxxxx/node_modules/@angular-devkit/build-angular/src/utils/differential-loading.js:15:29)
    at generateWebpackConfig (/Users/laco/Works/xxxxxx/node_modules/@angular-devkit/build-angular/src/utils/webpack-browser-config.js:25:35)
    at process._tickCallback (internal/process/next_tick.js:68:7)
    at Function.Module.runMain (internal/modules/cjs/loader.js:832:11)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)
  
Angular CLI: 8.0.0
Node: 10.16.0
OS: darwin x64
Angular: 8.0.0
... animations, cli, common, compiler, compiler-cli, core
... elements, forms, language-service, platform-browser
... platform-browser-dynamic, router
Package                            Version
------------------------------------------------------------
@angular-devkit/architect          0.800.0
@angular-devkit/build-angular      0.800.0
@angular-devkit/build-ng-packagr   0.800.0
@angular-devkit/build-optimizer    0.800.0
@angular-devkit/build-webpack      0.800.0
@angular-devkit/core               8.0.0
@angular-devkit/schematics         8.0.0
@angular/cdk                       7.3.4
@ngtools/json-schema               1.1.0
@ngtools/webpack                   8.0.0
@schematics/angular                8.0.0
@schematics/update                 0.800.0
ng-packagr                         5.2.0
rxjs                               6.5.2
typescript                         3.4.5
webpack                            4.30.0
Anything else relevant?
This seems the same problem to https://stackoverflow.com/questions/55681358/browserslisterror-unknown-browser-kaios
I saw something similar in our setup as well, which I had to fix in https://github.com/angular/angular-cli/pull/14303.
I'm not sure what we can do here. It seems like a dependency problem in browserslist.
Simple workaround for yarn is resolutions field in package.json and re-run yarn install --force.
{
  ....
  "resolutions": {
    "caniuse-lite": "1.0.30000971"
  }
}
                    We have the same issue with upgrade to angular 8 and @angular-devkit/architect 0.800.0
Same issue encountered while upgrading to v8 from v7. Upgraded node to v12.3.1 from v10.15.3 and running the below upgrade command
ng update @angular/cli @angular/core
Logs below :
ng serve
Unknown browser kaios
BrowserslistError: Unknown browser kaios
    at checkName (D:\fmcts\node_modules\browserslist\index.js:132:20)
    at Function.select (D:\fmcts\node_modules\browserslist\index.js:830:18)
    at D:\fmcts\node_modules\browserslist\index.js:176:33
    at Array.reduce (<anonymous>)
    at resolve (D:\fmcts\node_modules\browserslist\index.js:158:18)
    at browserslist (D:\fmcts\node_modules\browserslist\index.js:278:16)
    at Object.isSupported (D:\fmcts\node_modules\caniuse-api\dist\index.js:62:37)
    at Object.isEs5SupportNeeded (D:\fmcts\node_modules\@angular-devkit\build-angular\src\utils\differential-loading.js:22:21)
    at Object.getCommonConfig (D:\fmcts\node_modules\@angular-devkit\build-angular\src\angular-cli-files\models\webpack-configs\common.js:65:88)
    at D:\fmcts\node_modules\@angular-devkit\build-angular\src\browser\index.js:48:27
    at D:\fmcts\node_modules\@angular-devkit\build-angular\src\utils\webpack-browser-config.js:56:26
    at Array.map (<anonymous>)
    at generateWebpackConfig (D:\fmcts\node_modules\@angular-devkit\build-angular\src\utils\webpack-browser-config.js:31:26)
    at async Object.generateBrowserWebpackConfigFromContext (D:\fmcts\node_modules\@angular-devkit\build-angular\src\utils\webpack-browser-config.js:98:20)
    at async setup (D:\fmcts\node_modules\@angular-devkit\build-angular\src\dev-server\index.js:70:37)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] start: `ng serve`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\sartaj\AppData\Roaming\npm-cache\_logs\2019-05-30T04_22_22_135Z-debug.log
                    Is there any workaround for NPM?
Node v12.3.1
I had the same problem until I cleaned up a bit:
rm -fr node_modules
rm package-lock.json
npm i 
after that it worked.
doing what @shprink said also solved the problem for me.
I had the same problem until I cleaned up a bit:
rm -fr node_modules rm package-lock.json npm iafter that it worked.
My bad really...I did not do "npm install" at all after doing an upgrade from v7 to v8 (school boy mistake). I am doing that now but I have other issues to solve...Will post details as soon as I am done.
Having same issue all above does not fix it.
Unknown browser kaios
BrowserslistError: Unknown browser kaios
Unknown browser kaios
BrowserslistError: Unknown browser kaios
    at checkName (C:\git\node_modules\browserslist\index.js:171:20)
    at Function.select (C:\git\node_modules\browserslist\index.js:881:18)
    at C:\git\node_modules\browserslist\index.js:215:33
    at Array.reduce (<anonymous>)
    at resolve (C:\git\node_modules\browserslist\index.js:197:18)
    at browserslist (C:\git\node_modules\browserslist\index.js:317:16)
    at Object.isSupported (C:\git\node_modules\caniuse-api\dist\index.js:62:37)
    at Object.isEs5SupportNeeded (C:\git\node_modules\@angular-devkit\build-angular\src\utils\differential-loading.js:22:21)
    at Object.getCommonConfig (C:\git\node_modules\@angular-devkit\build-angular\src\angular-cli-files\models\webpack-configs\common.js:66:92)
    at C:\git\node_modules\@angular-devkit\build-angular\src\browser\index.js:48:27
    at C:\git\node_modules\@angular-devkit\build-angular\src\utils\webpack-browser-config.js:56:26
@Sevensnake the solution from @shprink worked to for me but i have to clean the cache, have u tried this ?
rm -rf node_modules
rm package-lock.json
# just to be sure
npm cache clean --force 
npm i
                    Hi all, is this still reproducible with Angular CLI 8.0.3?
Thanks for reporting this issue. This issue is now obsolete due to changes in the recent releases. Please update to the most recent Angular CLI version.
If the problem persists after upgrading, please open a new issue, provide a simple repository reproducing the problem, and describe the difference between the expected and current behavior.
This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.
Read more about our automatic conversation locking policy.
_This action has been performed automatically by a bot._
Most helpful comment
I had the same problem until I cleaned up a bit:
after that it worked.