Uglify is a pretty nifty javascript minifier but it also has the lesser-known ability to generate and walk the AST.
Unfortunately, uglify's traverser is a bit cumbersome to use so I wrote a library using my own traverser to make it easy!
Introducing burrito, a crazy new library to make AST traversals and manipulations crazy easy.
Given this snippet of code:
f() && g(h());
foo();
It's super easy to wrap all the function calls in another function call, qqq():
var burrito = require('burrito');
var src = burrito('f() && g(h())\nfoo()', function (node) {
if (node.name === 'call') node.wrap('qqq(%s)');
});
console.log(src);
$ node wrap.js
qqq(f()) && qqq(g(qqq(h())));
qqq(foo());
Or maybe dive in and surgically replace that && with a ||, how about!
var burrito = require('burrito');
var src = burrito('f() && g(h())\nfoo()', function (node) {
if (node.name === 'binary') node.wrap('%a || %b');
});
console.log(src);
$ node wrap.js
f() || g(h());
foo();
Plus you can .microwave() your burrito too, which evals the code using node's vm.runInNewContext() (which even runs in the browser thanks to browserify).
var burrito = require('burrito');
var res = burrito.microwave('Math.sin(2)', function (node) {
if (node.name === 'num') node.wrap('Math.PI / %s');
});
console.log(res);
This snippet takes the expression Math.sin(2) and replaces the 2 with Math.PI / 2 thanks to some %s interpolation. And since Math.sin(Math.PI / 2) evaluates at 1, the code should print as much...
$ node microwave.js
1
And it does! Hooray!
This craziness makes an amazing number of things possible, like stack traces that work in all the browsers without relying on a stack trace API or code coverage tools without any binary extensions!
Give burrito a spin!
npm install burrito
