title: jupyter lab build fails because of node
body: <p>I am using jupyter managed by anaconda. Trying to build extensions, I get the error:</p>
  
  <pre><code> &gt; jupyter lab build
  [LabBuildApp] JupyterLab 1.2.6
  [LabBuildApp] Building in /opt/anaconda3/share/jupyter/lab
  [LabBuildApp] Building jupyterlab assets (build:prod:minimize)
  [LabBuildApp] WARNING | 
  "nbdime-jupyterlab@2.0.0" is not compatible with the current JupyterLab
  Conflicting Dependencies:
  JupyterLab             Extension      Package
  &gt;=1.2.1 &lt;1.3.0         &gt;=2.0.0 &lt;3.0.0 @jupyterlab/apputils
  &gt;=3.2.0 &lt;3.3.0         &gt;=4.0.0 &lt;5.0.0 @jupyterlab/coreutils
  &gt;=1.2.2 &lt;1.3.0         &gt;=2.0.0 &lt;3.0.0 @jupyterlab/notebook
  &gt;=1.2.1 &lt;1.3.0         &gt;=2.0.0 &lt;3.0.0 @jupyterlab/rendermime
  &gt;=4.2.0 &lt;4.3.0         &gt;=5.0.0 &lt;6.0.0 @jupyterlab/services
  
  
  An error occured.
  RuntimeError: npm dependencies failed to install
  See the log file for details:  /var/folders/s4/msbdmzl11k1frxr21fdngkbw0000gn/T/jupyterlab-debug-cl5xoyof.log
  </code></pre>
  
  <p>Inspecting the log file:</p>
  
  <pre><code>[LabBuildApp] &gt; node /opt/anaconda3/lib/python3.7/site-packages/jupyterlab/staging/yarn.js install --non-interactive
  [LabBuildApp] yarn install v1.15.2
  [1/5] Validating package.json...
  [2/5] Resolving packages...
  warning @jupyterlab/plotly-extension &gt; plotly.js &gt; regl-splom &gt; left-pad@1.3.0: use String.prototype.padStart()
  warning @jupyterlab/plotly-extension &gt; plotly.js &gt; point-cluster &gt; bubleify &gt; buble &gt; os-homedir@2.0.0: This is not needed anymore. Use `require('os').homedir()` instead.
  [3/5] Fetching packages...
  error ws@7.2.1: The engine "node" is incompatible with this module. Expected version "&gt;=8.3.0". Got "6.13.1"
  error Found incompatible module
  info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
  
  [LabBuildApp] npm dependencies failed to install
  [LabBuildApp] Traceback (most recent call last):
  
  [LabBuildApp]   File "/opt/anaconda3/lib/python3.7/site-packages/jupyterlab/debuglog.py", line 47, in debug_logging
      yield
  
  [LabBuildApp]   File "/opt/anaconda3/lib/python3.7/site-packages/jupyterlab/labapp.py", line 98, in start
      command=command, app_options=app_options)
  
  [LabBuildApp]   File "/opt/anaconda3/lib/python3.7/site-packages/jupyterlab/commands.py", line 459, in build
      command=command, clean_staging=clean_staging)
  
  [LabBuildApp]   File "/opt/anaconda3/lib/python3.7/site-packages/jupyterlab/commands.py", line 660, in build
      raise RuntimeError(msg)
  
  [LabBuildApp] RuntimeError: npm dependencies failed to install
  
  [LabBuildApp] Exiting application: JupyterLab
  </code></pre>
  
  <p>The problem seems to be an outdated <code>node</code>. I have a current version of <code>node</code> on my system, but Anaconda seems to use its own older version. How could I upgrade this?</p>