I believe the issue is that .nycrc has a higher priority than package.json. So hint/package.json is being loaded, the extends is processed, but then .nycrc is found and overwrites your branches value again. Can you please try creating hint/.nycrc containing {}? This would block the root .nycrc from being found from within the hint directory. Another option is to just move your nyc options from hint/package.json to hint/.nycrc. I believe this should resolve the conflict.

Regarding what you see in the README I think the wording is not perfect. You can add options that overwrite the configuration being extended but they will overwrite (rather than merge). This is of particular interest if you are dealing with say @istanbuljs/nyc-config-babel which sets require: ['@babel/register']. Extending the babel config then setting require: ['ts-node/register'] would replace @babel/register.

Thanks @coreyfarrell for the suggestions, but unfortunately none seem to work or I don't know what I'm doing wrong 😞

• packages/hint/.nycrc with { } and current content in packages/hint/package.json fails
• packages/hint/.nycrc with the following content and removing the nyc property from packages/hint/package.json fails as well:

{
  "branches": 75,
  "extends": "../../.nycrc"
}

During theses tests I've seen that nyc will go up the tree until it finds a .nycrc file, which is pretty cool. Will remove a bunch of properties from other packages 😊

I'm seeing this problem too - again coming from the monorepo approach and trying to solve this from a few different angles.

The behaviour of extends seems to be broken since it takes the values coming from "extends" over any values defined in the config file.

package.json

"nyc": {
  "extends": "path/to/.nycrc",
  "all": true,
  "per-file": true,
  "lines": 80
}

path/to/.nycrc

{
  "lines": 100,
  "per-file": false
}

The resulting config that nyc loads looks like this

{
  "lines": 100,
  "per-file": false,
  "all": true
}

This needs to be fixed in https://github.com/istanbuljs/load-nyc-config and would probably be counted as another breaking change.

Having this problem too, just to confirm as a non-monorepo-usecase. We have multiple separate packages that use a shared nycrc.yaml that we add as a node_module:

extends: "@internal/nyc-config"
branches: 0

I can manually edit the extended config and nyc is definitely picking it up, but I can't override any of its options...

I was able to work around this by creating an nyc.config.js file at the root of my project and applying my overrides there.

nyc.config.js:

const settings = require('path/to/nyc-config');

settings.exclude = settings.exclude.concat([
  'nyc.config.js',
  'tools/**'
]);

settings.lines = 80;

module.exports = settings;

I am also experiencing this issue in "15.1.0". The common config file that we are reusing across projects is .nycrc, which makes it inconvenient to refactor (I would have to change in all other projects)

I believe the issue is in here. It overwrites the configuration with extended configuration but it should be the other way around.

For anyone else trying to work around this for a monorepo scenario, I was able to do so by adding my extends clause in a local package.json and putting the overrides in a local .nycrc. Both get picked up and the local .nycrc is applied last so the overrides still take effect.

See webhintio/hint@cca423d