extract-comments

extract-comments

Extract code comments from string or from a glob of files.

Heads up! As of v0.7.0 this no longer has a .fromFile() method to read from the file system. See [extracting from files].

Can be used with code-context to match comments up with related code.

Install with npm

npm i extract-comments --save

Usage

var extract = require('extract-comments');

// pass a string of javascript, CSS, LESS etc
extract(string);

Example

var str = '/**\n * this is\n *\n * a comment\n*/\nvar foo = "bar";\n';
extract(str);

Results in:

// key is the starting line number
{ '1':
   { begin: 1,
     end: 5,
     // line number of the code after the comment
     codeStart: 7 } }
     content: 'this is\n\na comment\n',
     // sames as content, but split into blocks at double newlines
     blocks: [
       'this is',
       'a comment\n'
     ],
     // first line of code after the comment
     after: 'var foo = "bar";',

(The reason the key is the starting line number is that it's easy to use this format with templates)

Customize output

// use code-context to parse the first line of code following
// the comment
var context = require('code-context');

// pass a function to modify the returned object
// and avoid looping more than once
var comments = extract(str, function(comment) {
  comment.context = context(comment.after);
  return comment;
});

Results in:

{ begin: 1,
  content: 'this is\n\na comment\n',
  after: 'var foo = "bar";',
  end: 5,
  codeStart: 7,
  blocks: [ 'this is', 'a comment\n' ],
  context:
   [ { begin: 1,
       type: 'declaration',
       name: 'foo',
       value: '"bar"',
       string: 'foo',
       original: 'var foo = "bar";' } ] }

Extracting from files

Prior to v0.7.0, there was a method to extract code comments from files. Here is the equivalent code to accomplish the same thing:

var fs = require('fs');
var extract = require('extract-comments');
var mapFiles = require('map-files');

function extractComments(patterns, opts) {
  opts = opts || {};
  opts.name = opts.rename || function(fp) {
    return fp;
  };
  opts.read = opts.read || function(fp, options) {
    var code = fs.readFileSync(fp, 'utf8');
    return extract(code, options);
  };
  return mapFiles(patterns, opts);
}

Related

• parse-comments: Parse code comments from JavaScript or any language that uses the same format.
• code-context: Parse a string of javascript to determine the context for functions, variables and comments based on the code that follows.
• esprima-extract-comments: Extract code comments from string or from a glob of files using esprima.

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue

Run tests

Install dev dependencies.

npm i -d && npm test

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright (c) 2014-2015 Jon Schlinkert
Released under the MIT license

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This file was generated by verb-cli on March 12, 2015.