CODEWITHSUNDEEP
typescriptnpm
Jordi
Jordi

Reputation: 23257

A package.json file without dependencies?

Trying to figure out what peerDependencies stands for... I came up with this package.json content file. It belongs to a library project which is distributed over there.

{
    "name": "...",
    "version": "...",
    "description": "...",
    "author": "...",
    "license": "Unlicense",
    "main": "dist/index.js",
    "typings": "dist/index.d.ts",
    "scripts": {
      "build": "typings install && tsc --outDir dist/"
    },
    "peerDependencies": {
        "@angular/core": "^2.0.0",   <<<<<<<<
        "@angular/http": "^2.0.0",   <<<<<<<<
        "@angular/common": "^2.0.0",   <<<<<<<<
        "@angular/compiler": "^2.0.0",   <<<<<<<<
        "core-js": "^2.4.0",   <<<<<<<<
        "reflect-metadata": "^0.1.3",   <<<<<<<<
        "rxjs": "5.0.0-beta.12",   <<<<<<<<
        "zone.js": "^0.6.17"   <<<<<<<<
      },
      "devDependencies": {
        "@angular/core": "^2.0.0",   <<<<<<<<
        "@angular/http": "^2.0.0",   <<<<<<<<
        "@angular/common": "^2.0.0",   <<<<<<<<
        "@angular/compiler": "^2.0.0",
        "@angular/platform-browser": "^2.0.0",   <<<<<<<<
        "core-js": "^2.4.0",   <<<<<<<<
        "reflect-metadata": "^0.1.3",   <<<<<<<<
        "rxjs": "5.0.0-beta.12",   <<<<<<<<
        "zone.js": "^0.6.17",   <<<<<<<<
        "typescript": "^2.0.0",
        "typings": "^1.3.2"
      }
}
  1. Why a same package is added on devDependencies and on peerDependencies?
  2. Why dependencies is not used?

Upvotes: 0

Views: 245

Answers (1)

Bruno Grieder
Bruno Grieder

Reputation: 29834

Since npm 3, peerDependencies are not automatically downloaded anymore. Instead nom will warn if a dependency is not already installed.

The reason for structuring a package.json this way that I would imagine is:

  • developers of this package need to download and install the dependencies and use the list in devDependencies

  • consumers of this package do not necessarily need to download the dependencies as they may already have them installed in their project. However, if they do not already have them, the presence of peerDependencies will guarantee they will get a warning on install (which they will need to resolve manually).

Upvotes: 1

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