get-pkg-prop

get-pkg-prop

Pass a key name & get the corresponding value from the intended package.json

Getting Started

Install

npm install get-pkg-prop -S

Add to source

import { getPkgProp } from "get-pkg-prop";

Use

import { getPkgProp } from 'get-pkg-prop'

const pkgMock = { version: "1.0.0", custom: { foo: "bar", baz: "bax" }   }

(async () => {
  await getPkgProp("name");
  // --> "get-pkg-prop"
  await getPkgProp("version", "path/to/child/module");
  // --> "x.y.z"
  await getPkgProp("custom", pkgMock)
  // --> { foo: "bar", baz: "bax" }
  await getPkgProp("fakeprop");
  // --> false
})

API

getPkgProp(szProperty)

Where

• szProperty is the name of the property.

How

• This uses pkg-up to find the closest package.json.

Why

• Useful for confirmations when toggling between local linked deps and remote installed deps. I wanted to enable modules to self-report relevant meta info (like their version)

import { getPkgProp } from 'get-pkg-prop'

(async () => {
  await getPkgProp("name")
  // --> "get-pkg-prop"
  await getPkgProp("version")
  // --> "0.2.6"
  await getPkgProp()
  // --> null; must provide property to check
  await getPkgProp("xyz")
  // --> false; property must exist in package.json
  await getPkgProp("repository")
  // --> { "type": "git", "url": "https://github.com/servexyz/get-pkg-prop" }
  */
})

getPkgProp(szProperty, oPackageJSON)

Where

• szProperty is the name of the property.
• oPackageJSON is the JSON object which contains your package

Why

• I added this for mock testing inline package objects.

import { getPkgProp } from 'get-pkg-prop'

const pkgMock = {
  "name": "my-pkg",
  "version": "1.0.0",
  "repository": {
      "type": "git",
      "url": "https://github.com/namespace/my-repo-pkg"
  }
}

(async () => {
  await getPkgProp("name", pkgMock)
  // --> "my-pkg"
  await getPkgProp("name")
  // --> "get-pkg-prop"; defaults to current pkg when unspecified
  await getPkgProp("version", pkgMock)
  // --> "0.2.6"
  await getPkgProp(, pkgMock)
  // --> null; must provide property to check
  await getPkgProp("xyz")
  // --> false; property must exist in package.json
  await getPkgProp("repository", pkgMock)
  // -->  { "type": "git", "url": "https://github.com/namespace/my-repo-pkg" }
  await getPkgProp("repository")
  // pkgMock wasn't specified, it returns value of cwd package:
  // -->  { "type": "git", "url": "https://github.com/servexyz/get-pkg-prop" }
})

getPkgProp(szProperty, szPathToPackageJSON)

Where

• szProperty is the name of the property.
• szPathToPackageJSON is the path to either your package.json file or the directory which contains the package.json file.

Why

• Specifying the path allows you to access the package of sub-modules or installed dependencies.

Note

• "path/to/child/module" and "path/to/child/module/package.json" are processed equally

import { getPkgProp } from 'get-pkg-prop'

(async () => {
  await getPkgProp("name")
  // --> "get-pkg-prop"; defaults to current pkg when unspecifeid
  await getPkgProp("name", "path/to/child/module")
  // --> "child-module-name"
  await getPkgProp("version", "path/to/child/module")
  // --> "x.y.z"
  await getPkgProp(,"path/to/child/module")
  // --> null; must provide property to check
  await getPkgProp("xyz", "path/to/child/module")
  // --> false; property must exist in package.json
  await getPkgProp("repository", "path/to/child/module")
  // --> { "type": "git", "url": "https://github.com/namespace/child-module-name" }
})

FAQ

Why

• Initially motivated by the desire to print package version
• Destructuring rocks. const { version } = require('./package.json').
  • Require's caching makes it difficult to use with development. Read more here
  • Unfortunately, Webpack throws a critical warning when using dynamic requires in certain circumstances (see example here). And while there are supposed fixes, I wanted to avoid the cluster altogether since I use webpack in almost every javascript project
• I wanted to have a more diverse API for different situations.
  • Module self-testing? Call get-pkg-prop("property") without specifying package.
  • Testing child-module? Call get-pkg-prop("property", "/sub/path/to/package.json") with package path specified.
  • Mock testing? Create a mock package JSON object and call it with get-pkg-prop("property", myPkgObj)

return scheme

• <null> - Whenever the <string> szProperty parameter is missing
• <string> - Whenever the property is found and extracted from the specified package object
• <false> - Whenever the property does not exist in the specified package object