build: update production build script (#437)

- Fix heap memory allocation issue
- Update package.json and .travis.yml

Fixes: #436

.travis.yml

@@ -11,7 +11,7 @@ before_script:
 
 script:
   - ng lint
-  - ng build --prod --output-hashing=none --base-href="/web-app/"
+  - npm run build:prod
 
 deploy:
   provider: pages
@@ -20,4 +20,4 @@ deploy:
   github-token: $GITHUB_TOKEN
   keep-history: true
   on:
-    branch: gsoc-19
+    branch: gsoc-19

package.json

@@ -13,6 +13,7 @@
   "scripts": {
     "ng": "ng",
     "build": "npm run env -s && ng build --prod --output-hashing=none",
+    "build:prod": "node --max-old-space-size=4096 ./node_modules/@angular/cli/bin/ng build --prod --output-hashing=none --base-href=\"/web-app/\"",
     "start": "npm run env -s && ng serve --aot --proxy-config proxy.conf.js",
     "serve:sw": "npm run build -s && npx http-server ./dist -p 4200",
     "lint": "ng lint && stylelint \"src/**/*.scss\" --syntax scss && htmlhint \"src\" --config .htmlhintrc",