How to fix ajv-errors installation

The bug

Mocks Server relies on ajv and ajv-errors for making validations. This may produce a bug in some projects when using npm 6.x due to a wrong installation of peerDependencies. In that case, Mocks Server will still work, but validations will be disabled.

The error is produced because ajv-errors@3.x has a peerDependency with ajv@8.x, and it doesn't work with lower ajv versions. Well, mocks-server declares both dependencies, but npm sometimes doesn't take this into account and provides wrong versions of the packages to mocks-server, which produces an error. This is an npm issue in versions lower than 7.x.

Workarounds

There are some workarounds to fix the error and make Mocks Server validations work properly if you face this issue in your project.

Try one of next possible workarounds:

• Install ajv@8.x in your project's peerDependencies:

npm i --save-dev ajv@8.x

• Upgrade to npm version 7 if you can

npm install -g npm@latest

• Use yarn rather than npm
• Modify manually your package-lock.json file and move the ajv and ajv-errors dependencies under the mocks-server dependencies property:

{
  "dependencies": {
    //...search for `ajv@8.x` and `ajv-errors@3.x` properties
    "ajv-errors": {
      "version": "3.0.0",
      //...
    },
    "ajv": {
      "version": "8.5.0",
      //...
    },
    "mocks-server": {
      //...
      "dependencies": {
        // Copy here both "ajv@8.x" and "ajv-errors@3.x" dependencies blocks
      }
    }
  }
}