diff --git a/jobs/templates/swh-pypi.groovy b/jobs/templates/swh-pypi.groovy
index f568d06..afd35a9 100644
--- a/jobs/templates/swh-pypi.groovy
+++ b/jobs/templates/swh-pypi.groovy
@@ -1,78 +1,84 @@
 def module_name = '{display-name}'.replace('-', '.')
 
 def PYPI_UPLOAD_HOST
 
 switch (params.PYPI_HOST) {{
   case 'pypi.org':
     PYPI_UPLOAD_HOST = 'upload.pypi.org'
     break
   default:
     PYPI_UPLOAD_HOST = params.PYPI_HOST
     break
 }}
 
 pipeline {{
   agent {{ label 'swh-tox' }}
 
   stages {{
     stage('Run tests') {{
       when {{
         expression {{ return !params.SKIP_TESTS }}
         beforeAgent true
       }}
       agent none
       steps {{
         build(
           job: '/{name}/tests',
           parameters: [
             string(name: 'REVISION', value: params.GIT_TAG),
           ],
           propagate: !params.IGNORE_TESTS,
         )
       }}
     }}
 
     stage('Checkout') {{
       steps {{
         checkout([$class: 'GitSCM',
                   branches: [[name: params.GIT_TAG]],
                   doGenerateSubmoduleConfigurations: false,
                   extensions: [],
                   gitTool: 'Default',
                   submoduleCfg: [],
                   userRemoteConfigs: [[url: 'https://forge.softwareheritage.org/source/{display-name}.git']]
         ])
       }}
     }}
 
     stage('Build') {{
       steps {{
-        sh 'python3 setup.py sdist bdist_wheel'
+        sh '''
+          if [ -f yarn.lock ]; then
+            yarn install --frozen-lockfile
+            yarn build
+          fi
+          python3 setup.py sdist bdist_wheel
+        '''
         archiveArtifacts allowEmptyArchive: true,
           artifacts: 'dist/*',
           fingerprint: true
       }}
     }}
 
     stage('Publish') {{
       when {{
         anyOf {{
           expression {{ return params.FORCE_UPLOAD }}
           expression {{
             LASTV=sh(returnStdout: true,
                      script:"curl -s https://${{params.PYPI_HOST}}/pypi/${{module_name}}/json | jq -r .info.version || true").trim()
             return 'v'+LASTV != params.GIT_TAG
             }}
         }}
       }}
       steps {{
         withCredentials([
           usernamePassword(credentialsId: PYPI_UPLOAD_HOST,
                            usernameVariable: 'TWINE_USERNAME',
                            passwordVariable: 'TWINE_PASSWORD')]) {{
           sh "python3 -m twine upload --repository-url https://${{PYPI_UPLOAD_HOST}}/legacy/ dist/*"
         }}
       }}
     }}
   }}
 }}