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Generic Express.js/Connect middleware handling runtime compilization tasks.


  • Compile source file on requested

  • Cache the compiled data for next request

  • Watch for source file changes

    Once the source file is changed, cache is invalidated.

  • Dependency Supplement interface

    Add extra dependency files to watch

  • Support JSONP request

    Support request with GET /api?callback=?


var compile = require('compile-middleware');
var midware = {
  less: compile({
    filename  : function (req) {            // Source filename resolve 
                  // Function obtaining filename  
    src       : '/path/to/source',          // Path to source file 
    render    : function (source_path, cb, depend) {
                  // Function render file  
  jade: compile({
    filename  : /(?:\/runtime\/)(.*)\.js/i, // Capture group 1 will be used 
    src_ext   : '.jade',                    // Optional, Default '' 
    src       : '/path/to/source',
    render    : function (source_path, cb) {
                  // Function rendering file 
    headers   : {                           // Optional, HTTP Headers 
                  'Cache-Control': 'public, max-age=86400',
                  'Content-Type': 'text/javascript' 

When render function issue an ENOENT error. The middleware will invoke the next() function for other middleware to execute.

Thus, put this middleware before express.static middleware is recommended practice.

Render Function Arguments:

  • source_path

    path to the file to be rendered, file path be made from src, filename expression and src_ext parameter.

  • cb

    callback function, invoke cb(err) on error, cb(null, <data>) on success

  • depend (Optional)

    You can add extra dependency by calling depend("/path/to/extra/depend") or depend(["list/of", "extra/depend", "files"])

    The change on depended file will also invalidate the compiled cache

Either a function or Regular Expression is accepted as filename parameter. When using RegEx, the first capture group will be used as the name of source file. A suffix to filename can be defined by src_ext.

WARNING No not add a g flag to the RegExp, that will broke the filename extraction procedure. It's an V8 Issue

Related Works


Copyright 2013 Shinohane<>

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.