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Version: 10.x

package.json

The manifest file of a package. It contains all the package's metadata, including dependencies, title, author, et cetera. This is a standard preserved across all major Node.js package managers, including pnpm.

In addition to the traditional package.json format, pnpm also supports package.json5 (via json5) and package.yaml (via js-yaml).

engines​

You can specify the version of Node and pnpm that your software works on:

{
    "engines": {
        "node": ">=10",
        "pnpm": ">=3"
    }
}

During local development, pnpm will always fail with an error message if its version does not match the one specified in the engines field.

Unless the user has set the engineStrict config flag (see settings), this field is advisory only and will only produce warnings when your package is installed as a dependency.

dependenciesMeta​

Additional meta information used for dependencies declared inside dependencies, optionalDependencies, and devDependencies.

dependenciesMeta.*.injected​

If this is set to true for a dependency that is a local workspace package, that package will be installed by creating a hard linked copy in the virtual store (node_modules/.pnpm).

If this is set to false or not set, then the dependency will instead be installed by creating a node_modules symlink that points to the package's source directory in the workspace. This is the default, as it is faster and ensures that any modifications to the dependency will be immediately visible to its consumers.

For example, suppose the following package.json is a local workspace package:

{
  "name": "card",
  "dependencies": {
    "button": "workspace:1.0.0"
  }
}

The button dependency will normally be installed by creating a symlink in the node_modules directory of card, pointing to the development directory for button.

But what if button specifies react in its peerDependencies? If all projects in the monorepo use the same version of react, then there is no problem. But what if button is required by card that uses react@16 and form that uses react@17? Normally you'd have to choose a single version of react and specify it using devDependencies of button. Symlinking does not provide a way for the react peer dependency to be satisfied differently by different consumers such as card and form.

The injected field solves this problem by installing a hard linked copies of button in the virtual store. To accomplish this, the package.json of card could be configured as follows:

{
  "name": "card",
  "dependencies": {
    "button": "workspace:1.0.0",
    "react": "16"
  },
  "dependenciesMeta": {
    "button": {
      "injected": true
    }
  }
}

Whereas the package.json of form could be configured as follows:

{
  "name": "form",
  "dependencies": {
    "button": "workspace:1.0.0",
    "react": "17"
  },
  "dependenciesMeta": {
    "button": {
      "injected": true
    }
  }
}

With these changes, we say that button is an "injected dependency" of card and form. When button imports react, it will resolve to react@16 in the context of card, but resolve to react@17 in the context of form.

Because injected dependencies produce copies of their workspace source directory, these copies must be updated somehow whenever the code is modified; otherwise, the new state will not be reflected for consumers. When building multiple projects with a command such as pnpm --recursive run build, this update must occur after each injected package is rebuilt but before its consumers are rebuilt. For simple use cases, it can be accomplished by invoking pnpm install again, perhaps using a package.json lifecycle script such as "prepare": "pnpm run build" to rebuild that one project. Third party tools such as pnpm-sync and pnpm-sync-dependencies-meta-injected provide a more robust and efficient solution for updating injected dependencies, as well as watch mode support.

peerDependenciesMeta​

This field lists some extra information related to the dependencies listed in the peerDependencies field.

peerDependenciesMeta.*.optional​

If this is set to true, the selected peer dependency will be marked as optional by the package manager. Therefore, the consumer omitting it will no longer be reported as an error.

For example:

{
    "peerDependencies": {
        "foo": "1"
    },
    "peerDependenciesMeta": {
        "foo": {
            "optional": true
        },
        "bar": {
            "optional": true
        }
    }
}

Note that even though bar was not specified in peerDependencies, it is marked as optional. pnpm will therefore assume that any version of bar is fine. However, foo is optional, but only to the required version specification.

publishConfig​

It is possible to override some fields in the manifest before the package is packed. The following fields may be overridden:

To override a field, add the publish version of the field to publishConfig.

For instance, the following package.json:

{
    "name": "foo",
    "version": "1.0.0",
    "main": "src/index.ts",
    "publishConfig": {
        "main": "lib/index.js",
        "typings": "lib/index.d.ts"
    }
}

Will be published as:

{
    "name": "foo",
    "version": "1.0.0",
    "main": "lib/index.js",
    "typings": "lib/index.d.ts"
}

publishConfig.executableFiles​

By default, for portability reasons, no files except those listed in the bin field will be marked as executable in the resulting package archive. The executableFiles field lets you declare additional files that must have the executable flag (+x) set even if they aren't directly accessible through the bin field.

{
  "publishConfig": {
    "executableFiles": [
      "./dist/shim.js"
    ]
  }
}

publishConfig.directory​

You also can use the field publishConfig.directory to customize the published subdirectory relative to the current package.json.

It is expected to have a modified version of the current package in the specified directory (usually using third party build tools).

In this example the "dist" folder must contain a package.json

{
  "name": "foo",
  "version": "1.0.0",
  "publishConfig": {
    "directory": "dist"
  }
}

publishConfig.linkDirectory​

  • Default: true
  • Type: Boolean

When set to true, the project will be symlinked from the publishConfig.directory location during local development.

For example:

{
  "name": "foo",
  "version": "1.0.0",
  "publishConfig": {
    "directory": "dist",
    "linkDirectory": true
  }
}