allow saving and loading in ast format

README.md

@@ -19,7 +19,7 @@ Usage
 ```
 $ jsfmt --help
 Usage:
-  jsfmt [--no-format] [--diff|--list|--write] [--validate] [--rewrite PATTERN|--search PATTERN] [--json] [<file>...]
+  jsfmt [--no-format] [--save-ast] [--diff|--list|--write] [--validate] [--rewrite PATTERN|--search PATTERN] [--json|--ast] [<file>...]
   jsfmt (--version | --help)
 
 Options:
@@ -31,6 +31,8 @@ Options:
   --no-format                    Do not format the input file(s)
   -w --write                     Overwrite the original file with jsfmt output
   -j --json                      Tell jsfmt that the file being parsed is json
+  -a --ast                       Tell jsfmt that the file being parsed is in JSON AST
+  --save-ast                     Output the resulting js in JSON AST format
   -r=PATTERN --rewrite PATTERN   Rewrite rule (e.g., 'a.slice(b, len(a) -> a.slice(b)')
   -s=PATTERN --search PATTERN    Search rule (e.g., 'a.slice')
 ```

lib/ast.js

@@ -0,0 +1,24 @@
+var escodegen = require('escodegen');
+var esprima = require('esprima');
+
+
+module.exports.parseAST = function(ast){
+  var js = escodegen.generate(ast, {
+    comment: true,
+    format: {
+      quotes: 'double'
+    }
+  });
+  return js;
+};
+
+module.exports.generateAST = function(js){
+  var ast = esprima.parse(js, {
+    raw: true,
+    tokens: true,
+    range: true,
+    comment: true
+  });
+  ast = escodegen.attachComments(ast, ast.comments, ast.tokens);
+  return ast;
+};

lib/index.js

@@ -1,6 +1,7 @@
 var rewritePath = './rewrite.js';
 var format = require('./format.js');
 var validate = require('./validate.js');
+var ast = require('./ast.js');
 
 exports.rewrite = require(rewritePath).rewrite;
 exports.search = require(rewritePath).search;
@@ -9,3 +10,5 @@ exports.formatJSON = format.formatJSON;
 exports.validate = validate.validate;
 exports.validateJSON = validate.validateJSON;
 exports.getConfig = require('./config.js').getConfig;
+exports.parseAST = ast.parseAST;
+exports.generateAST = ast.generateAST;

lib/run.js

@@ -15,7 +15,7 @@ tmp.setGracefulCleanup();
 
 var doc = [
   'Usage:',
-  '  jsfmt [--no-format] [--diff|--list|--write] [--validate] [--rewrite PATTERN|--search PATTERN] [--json] [<file>...]',
+  '  jsfmt [--no-format] [--save-ast] [--diff|--list|--write] [--validate] [--rewrite PATTERN|--search PATTERN] [--json|--ast] [<file>...]',
   '  jsfmt (--version | --help)',
   '',
   'Options:',
@@ -27,6 +27,8 @@ var doc = [
   '  --no-format                    Do not format the input file(s)',
   '  -w --write                     Overwrite the original file with jsfmt output',
   '  -j --json                      Tell jsfmt that the file being parsed is json',
+  '  -a --ast                       Tell jsfmt that the file being parsed is in JSON AST',
+  '  --save-ast                     Output the resulting js in JSON AST format',
   '  -r=PATTERN --rewrite PATTERN   Rewrite rule (e.g., \'a.slice(b, len(a) -> a.slice(b)\')',
   '  -s=PATTERN --search PATTERN    Search rule (e.g., \'a.slice\')',
 ].join("\r\n");
@@ -90,6 +92,10 @@ function handleJavascript(fullPath, original) {
   var js = original;
   var relativePath = path.relative(process.cwd(), fullPath);
 
+  if (argv['--ast']) {
+    js = jsfmt.parseAST(JSON.parse(js));
+  }
+
   if (argv['--search']) {
     try {
       jsfmt.search(js, argv['--search']).forEach(function(match) {
@@ -157,6 +163,13 @@ function handleJavascript(fullPath, original) {
     // Overwrite original file
     fs.writeFileSync(fullPath, js);
   } else {
+    if (argv['--save-ast']) {
+      var ast = jsfmt.generateAST(js);
+      js = JSON.stringify(ast);
+      if (!argv['--no-format']) {
+        js = jsfmt.formatJSON(js);
+      }
+    }
     // Print to stdout
     console.log(js);
   }

tests/ast.js

@@ -0,0 +1,28 @@
+/* jshint node:true */
+/* global describe,it */
+'use strict';
+var should = require('should');
+
+var libPath = process.env.JSFMT_COV ? 'lib-cov' : 'lib';
+var jsfmt = require('../' + libPath + '/index');
+
+describe('jsfmt.parseAST', function() {
+  it('should test basic ast json parsing', function() {
+    var ast = '{"type":"Program","body":[{"type":"VariableDeclaration","declarations":[{"type":"VariableDeclarator","id":{"type":"Identifier","name":"a","range":[4,5]},"init":{"type":"Literal","value":50,"raw":"50","range":[8,10]},"range":[4,10]}],"kind":"var","range":[0,11]},{"type":"VariableDeclaration","declarations":[{"type":"VariableDeclarator","id":{"type":"Identifier","name":"b","range":[16,17]},"init":{"type":"Literal","value":100,"raw":"100","range":[20,23]},"range":[16,23]}],"kind":"var","range":[12,24]}],"range":[0,24],"comments":[],"tokens":[{"type":"Keyword","value":"var","range":[0,3]},{"type":"Identifier","value":"a","range":[4,5]},{"type":"Punctuator","value":"=","range":[6,7]},{"type":"Numeric","value":"50","range":[8,10]},{"type":"Punctuator","value":";","range":[10,11]},{"type":"Keyword","value":"var","range":[12,15]},{"type":"Identifier","value":"b","range":[16,17]},{"type":"Punctuator","value":"=","range":[18,19]},{"type":"Numeric","value":"100","range":[20,23]},{"type":"Punctuator","value":";","range":[23,24]}]}';
+    ast = JSON.parse(ast);
+
+    var js = jsfmt.parseAST(ast);
+    js.should.eql('var a = 50;\nvar b = 100;');
+  });
+});
+
+describe('jsfmt.generateAST', function() {
+  it('should test basic ast generation', function() {
+    var js = 'var a = 50;\nvar b = 100;';
+    var ast = jsfmt.generateAST(js);
+
+    var astExpected = '{"type":"Program","body":[{"type":"VariableDeclaration","declarations":[{"type":"VariableDeclarator","id":{"type":"Identifier","name":"a","range":[4,5]},"init":{"type":"Literal","value":50,"raw":"50","range":[8,10]},"range":[4,10]}],"kind":"var","range":[0,11]},{"type":"VariableDeclaration","declarations":[{"type":"VariableDeclarator","id":{"type":"Identifier","name":"b","range":[16,17]},"init":{"type":"Literal","value":100,"raw":"100","range":[20,23]},"range":[16,23]}],"kind":"var","range":[12,24]}],"range":[0,24],"comments":[],"tokens":[{"type":"Keyword","value":"var","range":[0,3]},{"type":"Identifier","value":"a","range":[4,5]},{"type":"Punctuator","value":"=","range":[6,7]},{"type":"Numeric","value":"50","range":[8,10]},{"type":"Punctuator","value":";","range":[10,11]},{"type":"Keyword","value":"var","range":[12,15]},{"type":"Identifier","value":"b","range":[16,17]},{"type":"Punctuator","value":"=","range":[18,19]},{"type":"Numeric","value":"100","range":[20,23]},{"type":"Punctuator","value":";","range":[23,24]}]}';
+
+    JSON.stringify(ast).should.eql(astExpected);
+  });
+});