Do not drop peer/dev dep while saving if both set

Fix: npm/cli#1849

lib/add-rm-pkg-deps.js

@@ -21,6 +21,7 @@ const removeFromOthers = (name, type, pkg) => {
       break
     case 'peer':
     case 'peerOptional':
+      others.delete('devDependencies')
       others.delete('peerDependencies')
       others.delete('peerDependenciesMeta')
       break
@@ -44,9 +45,9 @@ const addSingle = ({pkg, spec, saveBundle, saveType}) => {
   const { name, rawSpec } = spec
   removeFromOthers(name, saveType, pkg)
   const type = saveType === 'prod' ? 'dependencies'
-    : saveType === 'dev' ? 'devDependencies'
     : saveType === 'optional' ? 'optionalDependencies'
     : saveType === 'peer' || saveType === 'peerOptional' ? 'peerDependencies'
+    : saveType === 'dev' ? 'devDependencies'
     : /* istanbul ignore next */ null
 
   pkg[type] = pkg[type] || {}
@@ -62,6 +63,10 @@ const addSingle = ({pkg, spec, saveBundle, saveType}) => {
       pdm[name].optional = true
       pkg.peerDependenciesMeta = pdm
     }
+    // peerDeps are often also a devDep, so that they can be tested when
+    // package managers that don't auto-install peer deps
+    if (pkg.devDependencies && pkg.devDependencies[name] !== undefined)
+      pkg.devDependencies[name] = pkg.peerDependencies[name]
   }
 
   if (saveBundle) {
@@ -82,16 +87,16 @@ const getSaveType = (pkg, spec) => {
     peerDependenciesMeta: peerDepsMeta,
   } = pkg
 
-  if (devDeps && devDeps[name] !== undefined)
-    return 'dev'
-  else if (optDeps && optDeps[name] !== undefined)
-    return 'optional'
-  else if (peerDeps && peerDeps[name] !== undefined) {
+  if (peerDeps && peerDeps[name] !== undefined) {
     if (peerDepsMeta && peerDepsMeta[name] && peerDepsMeta[name].optional)
       return 'peerOptional'
     else
       return 'peer'
-  } else
+  } else if (devDeps && devDeps[name] !== undefined)
+    return 'dev'
+  else if (optDeps && optDeps[name] !== undefined)
+    return 'optional'
+  else
     return 'prod'
 }
 

test/add-rm-pkg-deps.js

@@ -122,6 +122,30 @@ t.test('add', t => {
     devDependencies: { foo: '2' },
   }, 'update dev')
 
+  t.strictSame(add({
+    pkg: {
+      devDependencies: { foo: '1' },
+      peerDependencies: { foo: '1' },
+    },
+    add: [ foo2 ],
+  }), {
+    devDependencies: { foo: '2' },
+    peerDependencies: { foo: '2' },
+  }, 'update dev and peer together')
+
+  t.strictSame(add({
+    pkg: {
+      devDependencies: { foo: '1' },
+      peerDependencies: { foo: '1' },
+      peerDependenciesMeta: { foo: { optional: true }},
+    },
+    add: [ foo2 ],
+  }), {
+    devDependencies: { foo: '2' },
+    peerDependencies: { foo: '2' },
+    peerDependenciesMeta: { foo: { optional: true }},
+  }, 'update dev and peerOptional together')
+
   t.end()
 })