How to install OpenLayers using NPM

Question

There seem to be two OpenLayers packages available over NPM:

Option 1

npm install ol

which then can be used:

import OlMap from 'ol/map';
import OlView from 'ol/view';
import OlTile from 'ol/layer/tile';
import OlLayerVector from 'ol/layer/vector';
import OlSourceVector from 'ol/source/vector';

Option 2

npm install openlayers

import * as ol from 'openlayers';

Why two packages? What is the correct way, if any?

The second one looks more elegant to me, but OL's documentation actually mentions the first one: https://www.npmjs.com/package/openlayers

Answer 1

The NPM page explains the difference. Do not start a project with openlayers, it uses closure, which you most likely will not. ol is packaged as'state of art' ES2015 modules. It enables your compiler (eg webpack) to only package things you actually use.

For use with webpack, Rollup, Browserify, or other module bundlers, install the ol package:

npm install ol

For use with Closure Library (rare), install the openlayers package and read the tutorial.

npm install openlayers