lexical-scope

detect global and local lexical identifiers from javascript source code

example

var detect = require('lexical-scope');
var fs = require('fs');
var src = fs.readFileSync(__dirname + '/src.js');

var scope = detect(src);
console.log(JSON.stringify(scope,null,2));

input:

var x = 5;
var y = 3, z = 2;

w.foo();
w = 2;

RAWR=444;
RAWR.foo();

BLARG=3;

foo(function () {
    var BAR = 3;
    process.nextTick(function (ZZZZZZZZZZZZ) {
        console.log('beep boop');
        var xyz = 4;
        x += 10;
        x.zzzzzz;
        ZZZ=6;
    });
    function doom () {
    }
    ZZZ.foo();

});

console.log(xyz);

output:

$ node example/detect.js
{
  "locals": {
    "": [
      "x",
      "y",
      "z"
    ],
    "body.7.expression.body.7.arguments.0": [
      "BAR",
      "doom"
    ],
    "body.7.expression.body.7.arguments.0.body.body.1.expression.body.1.arguments.0": [
      "xyz",
      "ZZZZZZZZZZZZ"
    ],
    "body.7.expression.body.7.arguments.0.body.body.2": []
  },
  "globals": {
    "implicit": [
      "w",
      "foo",
      "process",
      "console",
      "xyz"
    ],
    "implicitProperties": {
      "w": [
        "foo"
      ],
      "foo": [
        "()"
      ],
      "process": [
        "nextTick"
      ],
      "console": [
        "log"
      ],
      "xyz": [
        "*"
      ]
    },
    "exported": [
      "w",
      "RAWR",
      "BLARG",
      "ZZZ"
    ]
  }
}

live demo

If you are using a modern browser, you can go to http://lexical-scope.forbeslindesay.co.uk/ for a live demo.

methods

var detect = require('lexical-scope')

var scope = detect(src)

Return a scope structure from a javascript source string src.

scope.locals maps scope name keys to an array of local variable names declared with var. The key name '' refers to the top-level scope.

scope.globals.implicit contains the global variable names that are expected to already exist in the environment by the script.

scope.globals.explicit contains the global variable names that are exported by the script.

scope.globals.implicitProperties contains the properties of global variable names that have been used. There are two special implicit property names:

• "()" - when an implicit variable has been called
• "*" - when an implicit variable has been used in a context that is not a property and not a call

install

With npm do:

npm install lexical-scope

license

MIT