nx/docs/shared/concepts/executors-and-configurations.md

title	description
Executors and Configurations	Learn about Nx executors, pre-packaged node scripts that run tasks consistently across projects, and how to configure them in project.json files.

Executors and Configurations

Executors are pre-packaged node scripts that can be used to run tasks in a consistent way.

In order to use an executor, you need to install the plugin that contains the executor and then configure the executor in the project's project.json file.

{
  "root": "apps/cart",
  "sourceRoot": "apps/cart/src",
  "projectType": "application",
  "generators": {},
  "targets": {
    "build": {
      "executor": "@nx/webpack:webpack",
      "options": {
        "outputPath": "dist/apps/cart",
        ...
      }
    },
    "test": {
      "executor": "@nx/jest:jest",
      "options": {
        ...
      }
    }
  }
}

Each project has targets configured to run an executor with a specific set of options. In this snippet, cart has two targets defined - build and test.

Each executor definition has an executor property and, optionally, an options and a configurations property.

• executor is a string of the form [package name]:[executor name]. For the build executor, the package name is @nx/webpack and the executor name is webpack.
• options is an object that contains any configuration defaults for the executor. These options vary from executor to executor.
• configurations allows you to create presets of options for different scenarios. All the configurations start with the properties defined in options as a baseline and then overwrite those options. In the example, there is a production configuration that overrides the default options to set sourceMap to false.

Once configured, you can run an executor the same way you would run any target:

nx [command] [project]
nx build cart

Browse the executors that are available in the plugin registry.

Run a Terminal Command from an Executor

If defining a new target that needs to run a single shell command, there is a shorthand for the nx:run-commands executor that can be used.

{
  "root": "apps/cart",
  "sourceRoot": "apps/cart/src",
  "projectType": "application",
  "generators": {},
  "targets": {
    "echo": {
      "command": "echo 'hello world'"
    }
  }
}

For more info, see the run-commands documentation

Build your own Executor

Nx comes with a Devkit that allows you to build your own executor to automate your Nx workspace. Learn more about it in the docs page about creating a local executor.

Running executors with a configuration

You can use a specific configuration preset like this:

nx [command] [project] --configuration=[configuration]
nx build cart --configuration=production

Use Task Configurations

The configurations property provides extra sets of values that will be merged into the options map.

{
  "build": {
    "executor": "@nx/js:tsc",
    "outputs": ["{workspaceRoot}/dist/libs/mylib"],
    "dependsOn": ["^build"],
    "options": {
      "tsConfig": "libs/mylib/tsconfig.lib.json",
      "main": "libs/mylib/src/main.ts"
    },
    "configurations": {
      "production": {
        "tsConfig": "libs/mylib/tsconfig-prod.lib.json"
      }
    }
  }
}

You can select a configuration like this: nx build mylib --configuration=production or nx run mylib:build:production.

The following code snippet shows how the executor options get constructed:

require(`@nx/jest`).executors['jest']({
  ...options,
  ...selectedConfiguration,
  ...commandLineArgs,
}); // Pseudocode

The selected configuration adds/overrides the default options, and the provided command line args add/override the configuration options.

Default Configuration

When using multiple configurations for a given target, it's helpful to provide a default configuration. For example, running e2e tests for multiple environments. By default it would make sense to use a dev configuration for day to day work, but having the ability to run against an internal staging environment for the QA team.

{
  "e2e": {
    "executor": "@nx/cypress:cypress",
    "options": {
      "cypressConfig": "apps/my-app-e2e/cypress.config.ts"
    },
    "configurations": {
      "dev": {
        "devServerTarget": "my-app:serve"
      },
      "qa": {
        "baseUrl": "https://some-internal-url.example.com"
      }
    },
    "defaultConfiguration": "dev"
  }
}

When running nx e2e my-app-e2e, the dev configuration will be used. In this case using the local dev server for my-app. You can always run the other configurations by explicitly providing the configuration i.e. nx e2e my-app-e2e --configuration=qa or nx run my-app-e2e:e2e:qa