webpack-dev-server: throw new Error('invalid "instanceof" keyword value ' + c);

Getting this error while running webpack-dev-server --config ./webpack.client.js --hot

Operating System: Mac OS High Sierra
Node Version: 9.9.0
NPM Version: 5.7.1
webpack Version: 4.1.1
webpack-dev-server Version:3.1.1 Full stacktrace

node_modules/webpack/node_modules/ajv-keywords/keywords/instanceof.js:52
    throw new Error('invalid "instanceof" keyword value ' + c);
    ^

Error: invalid "instanceof" keyword value Promise
    at getConstructor (node_modules/webpack/node_modules/ajv-keywords/keywords/instanceof.js:52:11)
    at Ajv.compile (node_modules/webpack/node_modules/ajv-keywords/keywords/instanceof.js:21:27)
    at Object.useCustomRule (node_modules/webpack/node_modules/ajv/lib/compile/index.js:275:26)
    at Object.generate_custom [as code] (node_modules/webpack/node_modules/ajv/lib/dotjs/custom.js:32:24)
    at Object.generate_validate [as validate] (node_modules/webpack/node_modules/ajv/lib/dotjs/validate.js:347:35)
    at Object.generate_anyOf [as code] (node_modules/webpack/node_modules/ajv/lib/dotjs/anyOf.js:34:27)
    at generate_validate (node_modules/webpack/node_modules/ajv/lib/dotjs/validate.js:347:35)
    at localCompile (node_modules/webpack/node_modules/ajv/lib/compile/index.js:87:22)
    at Ajv.compile (node_modules/webpack/node_modules/ajv/lib/compile/index.js:56:13)
    at Ajv._compile (node_modules/webpack/node_modules/ajv/lib/ajv.js:358:27)
    at Ajv.compile (node_modules/webpack/node_modules/ajv/lib/ajv.js:118:37)
    at validateObject (node_modules/webpack/lib/validateSchema.js:36:23)
    at validateSchema (node_modules/webpack/lib/validateSchema.js:31:10)
    at processConfiguredOptions (node_modules/webpack-cli/bin/convert-argv.js:156:48)
    at module.exports (node_modules/webpack-cli/bin/convert-argv.js:150:10)
    at Object.<anonymous> (node_modules/webpack-dev-server/bin/webpack-dev-server.js:234:54)

About this issue

Original URL
State: closed
Created 6 years ago
Reactions: 37
Comments: 18 (1 by maintainers)

Most upvoted comments

why do bad things happen to good people?

we manually hacked our package.json to use webpack 4.2.0 and this error goes away!

woo!

+51

silky on Mar 25, 2018

So this happened because webpack pushed breaking changes in a minor version and most people probably have their package.json file with a carrot or tilde in front of the webpack dependencies. Removing that carrot or tilde to freeze to the version specified and running npm install fixed the problem for me.

I think it’s extremely irresponsible for webpack to have made these breaking changes in a minor version. The webpack CLI separation should have only occurred in a major release. You have literally millions of people depending on this package, please put some more thought into release numbers.

+43

MgSam on Apr 12, 2018

I solved by lowerring my webpack-dev-server version,The problem is there

+28

DCbryant on Mar 27, 2018

@ndabAP 2.9.1

+20

DCbryant on Apr 3, 2018

remember to lower your webpack-dev-server globaly not localy use : npm install webpack-dev-server@2.9.1 -g --save-dev and after that you are set

+16

HamidOsouli-zz on Jul 20, 2018

npm install webpack-dev-server@2.x, works for me.

+11

kunwang0916 on Sep 27, 2018

npm i webpack@latest -g helps me

zvs001 on Apr 9, 2018

Had this issue today, and went away, after upgrading webpack to 4.5.0 and also installing webpack-cli locally…

rohan-paul on Apr 5, 2018

you can use npm run build instead of

AbuAmeeer on May 13, 2019

following worked for me npm install webpack-dev-server@2.11.0 --save-dev

imzubair10 on May 24, 2019

I had a similar issue but it was due to not having webpack-cli installed locally.

styks1987 on Apr 4, 2018