@npmcli/package-json

Programmatic API to update package.json files. Updates and saves files the same way the npm cli handles them.

Install

npm install @npmcli/package-json

Usage:

const PackageJson = require('@npmcli/package-json')
const pkgJson = await PackageJson.load(path)
// $ cat package.json
// {
//   "name": "foo",
//   "version": "1.0.0",
//   "dependencies": {
//     "a": "^1.0.0",
//     "abbrev": "^1.1.1"
//   }
// }

pkgJson.update({
  dependencies: {
    a: '^1.0.0',
    b: '^1.2.3',
  },
  workspaces: [
    './new-workspace',
  ],
})

await pkgJson.save()
// $ cat package.json
// {
//   "name": "foo",
//   "version": "1.0.0",
//   "dependencies": {
//     "a": "^1.0.0",
//     "b": "^1.2.3"
//   },
//   "workspaces": [
//     "./new-workspace"
//   ]
// }

There is also a helper function exported for opening a package.json file with no extra normalization or saving functionality.

const { readPackage } = require('@npmcli/package-json/lib/read-package')
const rawData = await readPackage('./package.json')
// rawData will now have the package.json contents with no changes or normalizations

API:

constructor()

Creates a new empty instance of PackageJson.

---

async PackageJson.create(path)

Creates an empty package.json at the given path. If one already exists it will be overwritten.

---

async PackageJson.load(path, opts = {})

Loads a package.json at the given path.

• opts: Object can contain:
  • create: Boolean if true, a new package.json will be created if one does not already exist. Will not clobber ane existing package.json that can not be parsed.

Example:

Loads contents of a package.json file located at ./:

const PackageJson = require('@npmcli/package-json')
const pkgJson = new PackageJson()
await pkgJson.load('./')

Throws an error in case a package.json file is missing or has invalid contents.

---

static async PackageJson.load(path)

Convenience static method that returns a new instance and loads the contents of a package.json file from that location.

• path: String that points to the folder from where to read the package.json from

Example:

Loads contents of a package.json file located at ./:

const PackageJson = require('@npmcli/package-json')
const pkgJson = await PackageJson.load('./')

---

async PackageJson.normalize()

Intended for normalizing package.json files in a node_modules tree. Some light normalization is done to ensure that it is ready for use in @npmcli/arborist

• path: String that points to the folder from where to read the package.json from
• opts: Object can contain:
  • strict: Boolean enables optional strict mode when applying the normalizeData step
  • steps: Array optional normalization steps that will be applied to the package.json file, replacing the default steps
  • root: Path optional git root to provide when applying the gitHead step
  • changes: Array if provided, a message about each change that was made to the packument will be added to this array

---

static async PackageJson.normalize(path, opts = {})

Convenience static that calls load before calling normalize

• path: String that points to the folder from where to read the package.json from
• opts: Object can contain:
  • strict: Boolean enables optional strict mode when applying the normalizeData step
  • steps: Array optional normalization steps that will be applied to the package.json file, replacing the default steps
  • root: Path optional git root to provide when applying the gitHead step
  • changes: Array if provided, a message about each change that was made to the packument will be added to this array

---

async PackageJson.prepare()

Like normalize but intended for preparing package.json files for publish.

---

static async PackageJson.prepare(path, opts = {})

Convenience static that calls load before calling prepare

• path: String that points to the folder from where to read the package.json from
• opts: Object can contain:
  • strict: Boolean enables optional strict mode when applying the normalizeData step
  • steps: Array optional normalization steps that will be applied to the package.json file, replacing the default steps
  • root: Path optional git root to provide when applying the gitHead step
  • changes: Array if provided, a message about each change that was made to the packument will be added to this array

---

async PackageJson.fix()

Like normalize but intended for the npm pkg fix command.

---

PackageJson.update(content)

Updates the contents of a package.json with the content provided.

• content: Object containing the properties to be updated/replaced in the package.json file.

Special properties like dependencies, devDependencies, optionalDependencies, peerDependencies will have special logic to handle the update of these options, such as sorting and deduplication.

Example:

Adds a new script named new-script to your package.json scripts property:

const PackageJson = require('@npmcli/package-json')
const pkgJson = await PackageJson.load('./')
pkgJson.update({
  scripts: {
    ...pkgJson.content.scripts,
    'new-script': 'echo "Bom dia!"'
  }
})

NOTE: When working with dependencies, it's important to provide values for all known dependency types as the update logic has some interdependence in between these properties.

Example:

A safe way to add a devDependency AND remove all peer dependencies of an existing package.json:

const PackageJson = require('@npmcli/package-json')
const pkgJson = await PackageJson.load('./')
pkgJson.update({
  dependencies: pkgJson.content.dependencies,
  devDependencies: {
    ...pkgJson.content.devDependencies,
    foo: '^foo@1.0.0',
  },
  peerDependencies: {},
  optionalDependencies: pkgJson.content.optionalDependencies,
})

---

get PackageJson.content

Getter that retrieves the normalized Object read from the loaded package.json file.

Example:

const PackageJson = require('@npmcli/package-json')
const pkgJson = await PackageJson.load('./')
pkgJson.content
// -> {
//   name: 'foo',
//   version: '1.0.0'
// }

---

async PackageJson.save()

Saves the current content to the same location used when calling load().

LICENSE

ISC