check-npm-versions

Enforces "peer" npm dependencies in Meteor packages.

Use this package if you are writing an Meteor package that depends on a given npm package is installed at the app level of projects you are installed in.

Usage

If you are depending on a npm-distributed React component, you don't want to Npm.depends() on the npm package in your Meteor package, as this will mean a second copy of React will be shipped client-side as a sub-dependency of your package. Instead, you can do:

import { checkNpmVersions } from 'meteor/tmeasday:check-npm-versions';
checkNpmVersions({
  'griddle-react': '0.3.x'
}, 'my:griddle-package');

const Griddle = require('griddle-react');

This must be run on the server so that it has access to the package.json of the package where it can examine the version that is installed.

This will prompt the user with an warning message if they do not install griddle-react at a correct version directly in their application. If they install no version at all, your require statement will subsequently fail.

In your install instructions, you'll still want to tell them to npm install --save griddle-react --- this will just tell them what's wrong if they do not.

Gotchas

use require statement

You must use require rather than import, unless you do the check in a separate file, as import is hoisted to the top of the file (and thus will error before the call to checkNpmVersions, which means the user won't see the helpful warning telling them what to do).

package subfolders

If you import or require a subfolder of a package and have no other references to the package, E.g.:

import 'packageName/subfolder';

checkNpmVersions will output an install failure warning.

checkNpmVersions depends on finding packageName/package.json for your package. The meteor modules-runtime package builds a data tree of all packages referenced in import or require statements. When packageName/subFolder is the only reference, modules-runtime only recognizes that subfolder and things within it and it cannot find packageName/package.json. This will cause checkNpmVersions to believe the package is not loaded, when in fact packaageName/subfolder has loaded fine.

This is easily remedied by whitelisting the package.json file:

if(false) {
  require('packageName/package.json`);
 }

.npm folder

Sometimes the modules-runtime can get confused about what is in the .npm folder and what is in the peer node_modules folder.

Make sure you do not have collisions with Npm.depends dependencies. Then you can "clean" build like this:

rm -rf /path/to/myPackage/.npm
cd /path/to/myProject
meteor reset
meteor run