espurify ================================ Clone new AST without extra properties [![Build Status](https://travis-ci.org/estools/espurify.svg?branch=master)](https://travis-ci.org/estools/espurify) [![NPM version](https://badge.fury.io/js/espurify.svg)](https://badge.fury.io/js/espurify) [![License](https://img.shields.io/badge/license-MIT-brightgreen.svg)](https://github.com/estools/espurify/blob/master/MIT-LICENSE.txt) [![Code Style](https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg)](https://github.com/Flet/semistandard) API --------------------------------------- ### var purifiedAstClone = espurify(originalAst) Returns new clone of `originalAst` but without extra properties. Leaves properties defined in [The ESTree Spec](https://github.com/estree/estree) (formerly known as [Mozilla SpiderMonkey Parser API](https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API)) only. Also note that extra informations (such as `loc`, `range` and `raw`) are eliminated too. `espurify` supports [ES5](https://github.com/estree/estree/blob/master/es5.md), [ES2015](https://github.com/estree/estree/blob/master/es2015.md), and [ES2017](https://github.com/estree/estree/blob/master/es2017.md) properties. ### var customizedCloneFunctionWithWhiteList = espurify.cloneWithWhitelist(whiteList) Returns customized function for cloning AST, with user-provided `whiteList`. ### var purifiedAstClone = customizedCloneFunctionWithWhiteList(originalAst) Returns new clone of `originalAst` by customized function. #### whiteList | type | default value | |:---------|:--------------| | `object` | N/A | `whiteList` is an object containing NodeType as keys and properties as values. ```js { ArrayExpression: ['type', 'elements'], ArrayPattern: ['type', 'elements'], ArrowFunctionExpression: ['type', 'id', 'params', 'body', 'generator', 'expression'], AssignmentExpression: ['type', 'operator', 'left', 'right'], ... ``` ### var customizedCloneFunction = espurify.customize(options) Returns customized function for cloning AST, configured by custom `options`. ### var purifiedAstClone = customizedCloneFunction(originalAst) Returns new clone of `originalAst` by customized function. #### options | type | default value | |:---------|:--------------| | `object` | `{}` | Configuration options. If not passed, default options will be used. #### options.extra | type | default value | |:--------------------|:--------------| | `array` of `string` | null | List of extra properties to be left in result AST. For example, functions returned by `espurify.customize({extra: ['raw']})` will preserve `raw` properties of `Literal`. Functions return by `espurify.customize({extra: ['loc', 'range']})` will preserve `loc` and `range` properties of each Node. EXAMPLE --------------------------------------- ```javascript 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 ```javascript var espurify = require('espurify'); ``` #### use espurify module on browser `espurify` function is exported ### via bower Install $ bower install --save espurify Load (`espurify` function is exported) AUTHOR --------------------------------------- * [Takuto Wada](https://github.com/twada) LICENSE --------------------------------------- Licensed under the [MIT](https://github.com/estools/espurify/blob/master/MIT-LICENSE.txt) license.