This example creates a two-pixel-wide red polyline that shows the path of the first trans-Pacific flight between Oakland, CA, and Brisbane, Australia.
Read the documentation.
Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.
git clone -b sample-polyline-simple https://github.com/googlemaps/js-samples.git
Other samples can be tried by switching to any branch beginning with
git checkout sample-SAMPLE_NAME