Package Exports

espurify

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (espurify) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

espurify

Clone new AST without extra properties

API

var purifiedAstClone = espurify(originalAst)

Returns new clone of originalAst but without extra properties.

Leave properties defined in Mozilla JavaScript AST spec only (Note: location informations are eliminated too).

EXAMPLE

var espurify = require('espurify'),
    estraverse = require('estraverse'),
    esprima = require('esprima'),
    syntax = estraverse.Syntax,
    assert = require('assert');

var jsCode = 'assert("foo")';

// Adding extra informations to AST
var originalAst = esprima.parse(jsCode, {tolerant: true, loc: true, raw: true});
estraverse.replace(originalAst, {
    leave: function (currentNode, parentNode) {
        if (currentNode.type === syntax.Literal && typeof currentNode.raw !== 'undefined') {
            currentNode['x-verbatim-bar'] = {
                content : currentNode.raw,
                precedence : 18  // escodegen.Precedence.Primary
            };
            return currentNode;
        } else {
            return undefined;
        }
    }
});


// purify AST
var purifiedClone = espurify(originalAst);


// original AST is not modified
assert.deepEqual(originalAst, {
  type: 'Program',
  body: [
    {
      type: 'ExpressionStatement',
      expression: {
        type: 'CallExpression',
        callee: {
          type: 'Identifier',
          name: 'assert',
          loc: {
            start: {
              line: 1,
              column: 0
            },
            end: {
              line: 1,
              column: 6
            }
          }
        },
        arguments: [
          {
            type: 'Literal',
            value: 'foo',
            raw: '"foo"',
            loc: {
              start: {
                line: 1,
                column: 7
              },
              end: {
                line: 1,
                column: 12
              }
            },
            "x-verbatim-bar": {
              content: '"foo"',
              precedence: 18
            }
          }
        ],
        loc: {
          start: {
            line: 1,
            column: 0
          },
          end: {
            line: 1,
            column: 13
          }
        }
      },
      loc: {
        start: {
          line: 1,
          column: 0
        },
        end: {
          line: 1,
          column: 13
        }
      }
    }
  ],
  loc: {
    start: {
      line: 1,
      column: 0
    },
    end: {
      line: 1,
      column: 13
    }
  },
  errors: []
});


// Extra properties are eliminated from cloned AST
assert.deepEqual(purifiedClone, {
    type: 'Program',
    body: [
        {
            type: 'ExpressionStatement',
            expression: {
                type: 'CallExpression',
                callee: {
                    type: 'Identifier',
                    name: 'assert'
                },
                arguments: [
                    {
                        type: 'Literal',
                        value: 'foo'
                    }
                ]
            }
        }
    ]
});

INSTALL

via npm

Install

$ npm install --save espurify

Use

var espurify = require('espurify');

via bower

Install

$ bower install --save espurify

Load (espurify function is exported)

<script type="text/javascript" src="./path/to/bower_components/espurify/build/espurify.js"></script>

AUTHOR

Takuto Wada

LICENSE

Licensed under the MIT license.