Closure: The Definitive Guide

Appendix C. plovr

plovr is a build tool for projects that use Closure. (Its name is the product of the animal on the cover of this book, the Web 2.0 zeitgeist, and domain name availability.) It can be run either as a web server (like the Closure Compiler Service introduced in Chapter 12), or as a command-line build script (like calcdeps.py). The goal of plovr is to make development with Closure easier and faster. By integrating the Closure Library, Templates, and Compiler into a single application with a normalized set of input options, it is considerably easier to get up and running with Closure from a single download. Furthermore, because plovr can be run as a web server, it can store information from previous compilations in memory, making subsequent compilations faster.

When running plovr as a web server, it provides a number of services that can help with development:

• Displays warnings and errors from the Compiler at the top of the web page that loads the compiled JavaScript with links to the line number where the warning or error occurred.

• Automatically compiles Soy files (as indicated by files whose names end in .soy) to JavaScript files.

• Provides a view that compares the size of the original code to that of the compiled code. This is done on a per-file basis so that it is possible to identify which input files are contributing the most code to the compiled output.

• Generates an externs file from the calls to goog.exportSymbol() and goog.exportProperty() in the input.

• Generates ...