Javascript parsing using NodeJS

Question

Is there any module to parse javascript using node.js . I mean we are able to add and remove html content dynamically using cheerio nodejs module.

Similarly, we want to add, remove and manipulate a javascript method/variable. Is there any module to do that. I searched but unable to get one.

Thanks in Advance !!!

• jfriend00: Do you just want eval()?

Answer 1

I would recommend the recast module. Install it via npm install --save recast. Below is a sample program that will read in the source of a module named user.js in the current directory. It will parse the source into an AST then from the AST re-generate the original source. Modify the AST with help from estraverse before you call recast.print(ast).code.

The source (does not incorporate estraverse -- exercise for the reader):

'use strict';
var recast = require('recast');
var path = require('path');
var fs = require('fs');
var file = path.resolve(__dirname, 'user.js');
var code = fs.readFileSync(file).toString();
var ast = recast.parse(code);
var output = recast.print(ast).code;
console.log(output);