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| r789 | # falafel | |||
| Transform the [ast](http://en.wikipedia.org/wiki/Abstract_syntax_tree) on a | ||||
| recursive walk. | ||||
| [](http://ci.testling.com/substack/node-falafel) | ||||
| [](https://github.com/substack/node-falafel/actions) | ||||
| This modules uses [acorn](https://npmjs.org/package/acorn) to create an AST from | ||||
| source code. | ||||
|  | ||||
| # example | ||||
| ## array.js | ||||
| Put a function wrapper around all array literals. | ||||
| ``` js | ||||
| var falafel = require('falafel'); | ||||
| var src = '(' + function () { | ||||
| var xs = [ 1, 2, [ 3, 4 ] ]; | ||||
| var ys = [ 5, 6 ]; | ||||
| console.dir([ xs, ys ]); | ||||
| } + ')()'; | ||||
| var output = falafel(src, function (node) { | ||||
| if (node.type === 'ArrayExpression') { | ||||
| node.update('fn(' + node.source() + ')'); | ||||
| } | ||||
| }); | ||||
| console.log(output); | ||||
| ``` | ||||
| output: | ||||
| ``` | ||||
| (function () { | ||||
| var xs = fn([ 1, 2, fn([ 3, 4 ]) ]); | ||||
| var ys = fn([ 5, 6 ]); | ||||
| console.dir(fn([ xs, ys ])); | ||||
| })() | ||||
| ``` | ||||
| # methods | ||||
| ``` js | ||||
| var falafel = require('falafel') | ||||
| ``` | ||||
| ## falafel(src, opts={}, fn) | ||||
| Transform the string source `src` with the function `fn`, returning a | ||||
| string-like transformed output object. | ||||
| For every node in the ast, `fn(node)` fires. The recursive walk is a | ||||
| post-order traversal, so children get called before their parents. | ||||
| Performing a post-order traversal makes it easier to write nested transforms since | ||||
| transforming parents often requires transforming all its children first. | ||||
| The return value is string-like (it defines `.toString()` and `.inspect()`) so | ||||
| that you can call `node.update()` asynchronously after the function has | ||||
| returned and still capture the output. | ||||
| Instead of passing a `src` you can also use `opts.source`. | ||||
| All of the `opts` will be passed directly to | ||||
| [acorn](https://npmjs.org/package/acorn). | ||||
| ## custom parser | ||||
| You may pass in an instance of acorn to the opts as `opts.parser` to use that | ||||
| version instead of the version of acorn packaged with this library. | ||||
| ```js | ||||
| var acorn = require('acorn-jsx'); | ||||
| falafel(src, {parser: acorn, plugins: { jsx: true }}, function(node) { | ||||
| // this will parse jsx | ||||
| }); | ||||
| ``` | ||||
| # nodes | ||||
| Aside from the regular [acorn](https://npmjs.org/package/acorn) data, you can also call | ||||
| some inserted methods on nodes. | ||||
| Aside from updating the current node, you can also reach into sub-nodes to call | ||||
| update functions on children from parent nodes. | ||||
| ## node.source() | ||||
| Return the source for the given node, including any modifications made to | ||||
| children nodes. | ||||
| ## node.update(s) | ||||
| Transform the source for the present node to the string `s`. | ||||
| Note that in `'ForStatement'` node types, there is an existing subnode called | ||||
| `update`. For those nodes all the properties are copied over onto the | ||||
| `node.update()` function. | ||||
| ## node.parent | ||||
| Reference to the parent element or `null` at the root element. | ||||
| # install | ||||
| With [npm](http://npmjs.org) do: | ||||
| ``` | ||||
| npm install falafel | ||||
| ``` | ||||
| # license | ||||
| MIT | ||||