A proof of concept Handlebars to JSP Transformer for those that aren't super stoked on the mighty behemoth that is the Wild West of JSP.
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README.md

Gulp Handlebars -> JSP Transpiler

A proof of concept Handlebars to JSP Transpiler for those that aren't super stoked on the mighty behemoth that is the Wild West of JSP.

Obviously compilers/transformers should have their output checked, and this is meant to streamline the development process and give a potential for another front end option that's a little easier on the eyes than JSP (and brain), and give a starting point so JSP development is more along the polishing side.

image

Installation

Just git clone the repo and npm install it up.

Commands

  • gulp handlebars: Compile Handlebars files to /build/html/**.html.
  • gulp jsp-compile: Compile Handlebars files to /build/jsp/**.jsp.

Completed Transforms

The current completed transforms are incredibly basic but a step in the right direction. Included in this are:

  • {{user.name}} -> ${user.name}
  • {{#if user}} {{/if}} -> <c:if test="${user}"> </c:if>
  • {{#unless user.ignoreUser}} {{/unless}} -> <c:if test="${!user.ignoreUser}"> </c:if>
  • {{#each users}} {{/each}} -> <c:forEach var="user" items="${users}"> </c:forEach>
    • Any {{ prop }} within the {{#each users}} block will be transformed to ${user.prop}
  • {{#with user}} {{/with}} -> deleted
    • Any {{ prop }} within the {{#with user}} block will be transformed to ${user.prop}
  • {{!-- comment --}} -> <%-- comment --%>
  • {{! comment }} -> <%-- comment --%>

To-do

  • Support for complex if else blocks being transformed to <c:choose> <c:when test /> <c:otherwise /> </c:choose> blocks.
  • Support for {{else}} sections within {{#with}} blocks.
  • varStatus support
    • {{@index}} -> ${varStatus.index}
    • {{@first}} -> ${varStatus.first}
    • {{@last}} -> ${varStatus.last}

Adding New Transforms

Transforms are added by creating a new file.js within the ./gulp-utils/statements/ folder with a dev-friendly name, regex expression for matching, and replacing function. The gulp setup will automatically get and use any .js files within that directory.

Example file var.js:

// Utils
var gutil = require('gulp-util'), // Only necessary for logging
    input = gutil.colors.green, // Only necessary for logging
    output = gutil.colors.magenta; // Only necessary for logging

// Transform block
module.exports = {
  // Dev friendly name
  name: "{{var}}",
  // Regex for matching Handlebars expression
  regex: /(\{{2}(\w+[\w.\/]*)\}{2}|\{{2} ([\w.\/]*) \}{2})/,
  // Replace function
  // Uses match to log the output and returns the full input with the replaced expression
  replace: function replaceVar(match) { // Replace function, takes match and 
    var content = match[2] || match[3];
    gutil.log(input(match[0]), '->', output('${'+content+'}'));
    return match['input'].replace(match[0], '${'+content+'}');
  }
};