chore: update npm scripts and synth.py (#767)

Update npm scripts: add clean, prelint, prefix; make sure that lint and fix are set properly. Use post-process feature of synthtool.

packages/google-cloud-vision/package.json

@@ -29,7 +29,7 @@
   "scripts": {
     "test": "c8 mocha build/test",
     "samples-test": "cd samples/ && npm link ../ && npm install && npm test && cd ../",
-    "lint": "gts fix",
+    "lint": "gts check",
     "docs": "jsdoc -c .jsdoc.js",
     "system-test": "mocha build/system-test",
     "fix": "gts fix",
@@ -40,7 +40,8 @@
     "clean": "gts clean",
     "compile": "tsc -p . && cp -r protos build/",
     "compile-protos": "compileProtos src",
-    "prepare": "npm run compile"
+    "prepare": "npm run compile",
+    "precompile": "gts clean"
   },
   "dependencies": {
     "@google-cloud/promisify": "^2.0.0",

packages/google-cloud-vision/synth.py

@@ -16,7 +16,7 @@
 
 import synthtool as s
 import synthtool.gcp as gcp
-import subprocess
+import synthtool.languages.node as node
 import logging
 
 logging.basicConfig(level=logging.DEBUG)
@@ -52,7 +52,4 @@
 templates = common_templates.node_library(source_location='build/src')
 s.copy(templates)
 
-# Node.js specific cleanup
-subprocess.run(['npm', 'install'])
-subprocess.run(['npm', 'run', 'fix'])
-subprocess.run(['npx', 'compileProtos', 'src'])
+node.postprocess_gapic_library()