Split Azure DevOps npm install/ci commands into different steps.

azure-pipelines.yml

@@ -1,17 +1,35 @@
 # Azure DevOps Pipeline for Node.js
 # https://docs.microsoft.com/azure/devops/pipelines/languages/javascript
 
-parameters:
-  osList: [ 'ubuntu', 'macos', 'windows' ]
-  nodeList: [ '8', '10', '12' ]
-
 strategy:
   matrix:
-    ${{ each os in parameters.osList }}:
+    linux_node_8:
-      ${{ each nv in parameters.nodeList }}:
+      imageName: 'ubuntu-latest'
-        ${{ format('{0}_node_{1}', os, nv) }}:
+      node_version: 8.x
-          imageName: ${{ format('{0}-latest', os) }}
+    linux_node_10:
-          node_version: ${{ format('{0}.x', nv) }}
+      imageName: 'ubuntu-latest'
+      node_version: 10.x
+    linux_node_12:
+      imageName: 'ubuntu-latest'
+      node_version: 12.x
+    macos_node_8:
+      imageName: 'macos-latest'
+      node_version: 8.x
+    macos_node_10:
+      imageName: 'macos-latest'
+      node_version: 10.x
+    macos_node_12:
+      imageName: 'macos-latest'
+      node_version: 12.x
+    windows_node_8:
+      imageName: 'windows-latest'
+      node_version: 8.x
+    windows_node_10:
+      imageName: 'windows-latest'
+      node_version: 10.x
+    windows_node_12:
+      imageName: 'windows-latest'
+      node_version: 12.x
 
 pool:
   vmImage: $(imageName)
@@ -22,6 +40,8 @@ steps:
     versionSpec: $(node_version)
   displayName: 'Install Node.js'
 
+- script: 'npm install --no-package-lock'
+  displayName: 'Install Dependencies'
 
-- script: 'npm install --no-package-lock && npm run ci'
+- script: 'npm run ci'
-  displayName: 'npm install and run ci'
+  displayName: 'Run Tests'