falafelify

Serve up fresh falafel from your browserify bundles.

What?

This is a browserify transform that runs your files through falafel. Basically you can alter your scripts by modifying the abstract syntax tree that they are parsed in to.

Installation

npm i --save falafelify

Or if you want something a little more fresh:

npm i --save KenPowers/falafelify

Usage

Here are some examples that I stole borrowed adapted from falafel as well as an original example (also available under the examples directory):

Wrap Arrays

This example shows how to wrap arrays (including nested arrays) in a function call.

arrays.js:

(function () {
  var xs = [1, 2, [3, 4]];
  var ys = [5, 6];
  console.dir([xs, ys]);
})();

build.js:

var browserify = require('browserify'),
    falafelify = require('falafelify'),
    fs = require('fs');
 
// Browserify build
browserify('./arrays')
  .transform(falafelify(function (node) {
    if (node.type === 'ArrayExpression') {
      node.update('fn(' + node.source() + ')');
    }
  }))
  .bundle()
  .pipe(fs.createWriteStream('out.js'));

Run node build and get the following:

out.js:

(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
(function () {
  var xs = fn([1, 2, fn([3, 4])]);
  var ys = fn([5, 6]);
  console.dir(fn([xs, ys]));
})();
 
},{}]},{},[1]);

Custom Keywords

This example shows how to create a custom keyword. In this case beep is a unary operator which converts its argument to a String and uppercases it:

keywords.js:

console.log(beep 'boop', 'BOOP');

build.js:

var browserify = require('browserify'),
    falafelify = require('falafelify'),
    fs = require('fs');
 
// Determines if a given identifier is a keyword
function isKeyword(id) {
  return id === 'beep';
}
 
// Browserify build, notice the `isKeyword` option passed to falafelify.
browserify('./keywords')
  .transform(falafelify({isKeyword: isKeyword}, function (node) {
    if (node.type === 'UnaryExpression' && node.keyword === 'beep') {
      node.update('String(' + node.argument.source() + ').toUppercase()');
    }
  }))
  .bundle()
  .pipe(fs.createWriteStream('out.js'));

Run node build and get the following:

out.js:

(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
console.log(String('boop').toUppercase(), 'BOOP');
 
},{}]},{},[1]);

Async

Unlike the regular falafel, falafelify lets you use async functions as your iterator using standard node callbacks (by default running 10 asynchronous operations at a time). This example shows how to update ast nodes asynchronously while changing the limit from 10 to 20:

async.js:

console.log(2 + 2);
console.log(2 - 2);
console.log(2 * 2);
console.log(2 / 2);

build.js:

var browserify = require('browserify'),
    falafelify = require('falafelify'),
    fs = require('fs');
 
// Determines if a node represents a binary math expression
function basicMath(node) {
  return node.type === 'BinaryExpression'
    && '+-*/'.indexOf(node.operator) > -1
    && node.left.type === 'Literal'
    && node.right.type === 'Literal';
}
 
// Async function which, given a BinaryExpression node, performs basic binary
// math expressions and updates the node with the calculated value.
function evaluate(node, done) {
  var o = node.operator, left = node.left.value, right = node.right.value;
  setTimeout(function () {
    if (o === '+') {
      node.update(left + right);
    } else if (o === '-') {
      node.update(left - right);
    } else if (o === '*') {
      node.update(left * right);
    } else if (o === '/') {
      node.update(left / right);
    } else {
      return done(new Error('Invalid operator.'));
    }
    // Make sure you ALWAYS call done.
    done();
  }, 250);
}
 
// Browserify build
browserify('./async')
  // First argument is the iterator, second argument is the parallel limit.
  .transform(falafelify(function (node, done) {
    if (basicMath(node)) {
      evaluate(node, done);
    } else {
      // Make sure you ALWAYS call done.
      done();
    }
  }, 20))
  .bundle()
  .pipe(fs.createWriteStream('out.js'));

Run node build and get the following:

out.js:

(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
console.log(4);
console.log(0);
console.log(4);
console.log(1);
 
},{}]},{},[1]);

Of course you could also be evil and use eval:

function evaluate(node, done) {
  setTimeout(function () {
    node.update(eval(node.source()));
    done();
  }, 250);
}

By default falafelify will only run 10 asynchronous operations at the same time. If this isn't enough for you then see the next section, API.

API

All of the following invocations are valid:

// Just a function (callback optional)
falafelify(fn);
// Options and function
falafelify(opts, fn);
// Function and parallel limit (number, defaults to 10)
falafelify(fn, limit);
// Options, function, and parallel limit (number, defaults to 10)
falafelify(opts, fn, limit);

License

The MIT License (MIT)

Copyright (c) 2015 Kenneth Powers

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.