Download of JSPower 3.0 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The application lies within Developer Tools, more precisely Webmaster Tools. The actual developer of this free Mac application is everettjf.
From the developer:
JSPower for Xcode is an Xcode extension. It provides a development interface for the JavaScript language. Anyone can create Xcode extension utilities using Javascript. For the built-in utilities, you can convert the selected text into ASCII text and sort selected lines.
You may want to check out more Mac applications, such as Url Extractor X, Boks or Navicat for Oracle, which might be similar to JSPower.