# espurify > Clone AST without extra properties Latest version **3.2.0** (published 2024-12-22) · MIT license · 0 weekly downloads ## Install ```sh npm install espurify pnpm add espurify yarn add espurify bun add espurify ``` ## Health **Score 35/100 (D)** — status: stable. Positive: no vulnerabilities. Warnings: low downloads; no types; no esm support. Negative: stale. ## Facts | | | |---|---| | Version | 3.2.0 | | Published | 2024-12-22 | | First published | 2014-07-22 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | none | | Module format | CommonJS | | Dependencies | 0 | | Unpacked size | 44.6 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 31 | | Author | Takuto Wada | | Maintainers | twada | | Keywords | ast, estree, ecmascript, es6 | ## Links - npm: https://www.npmjs.com/package/espurify - Repository: https://github.com/estools/espurify - Issues: https://github.com/estools/espurify/issues - npm.io page: https://npm.io/package/espurify ## Alternatives - [update-check](https://npm.io/package/update-check.md) — 4.0M weekly downloads - [react-native-onesignal](https://npm.io/package/react-native-onesignal.md) — 134.5K weekly downloads - [react-redux-toastr](https://npm.io/package/react-redux-toastr.md) — 33.7K weekly downloads - [@nocobase/plugin-notification-manager](https://npm.io/package/@nocobase/plugin-notification-manager.md) — 2.0K weekly downloads - [react-simple-toasts](https://npm.io/package/react-simple-toasts.md) — 1.9K weekly downloads ## Recent versions - 3.2.0 (latest) — 2024-12-22 - 3.1.0 — 2024-07-03 - 3.0.0 — 2022-07-17 - 2.1.1 — 2021-03-29 - 2.1.0 — 2021-03-25 - 2.0.1 — 2019-02-15 - 2.0.0 — 2018-11-23 - 1.8.1 — 2018-07-10 - 1.8.0 — 2018-05-10 - 1.7.0 — 2017-02-24 - 1.6.1 — 2017-02-13 - 1.6.0 — 2016-05-25 - 1.5.1 — 2016-03-28 - 1.5.0 — 2015-12-21 - 1.4.0 — 2015-12-18 - … 9 more at https://npm.io/package/espurify/versions ## README espurify ================================ Clone AST without extra properties [![Build Status][ci-image]][ci-url] [![NPM version][npm-image]][npm-url] [![Code Style][style-image]][style-url] [![License][license-image]][license-url] API --------------------------------------- ### const purifiedAstClone = espurify.purifyAst(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://speakerdeck.com/michaelficarra/spidermonkey-parser-api-a-standard-for-structured-js-representations)) only. Also note that extra informations (such as `loc`, `range` and `raw`) are eliminated too. (note: using `espurify` as a default exported function is deprecated in favor of named exports aiming ESM era, and will be removed in future major releases) #### Supported ECMAScript versions - [ES5](https://github.com/estree/estree/blob/master/es5.md) - [ES2015](https://github.com/estree/estree/blob/master/es2015.md) - [ES2016](https://github.com/estree/estree/blob/master/es2016.md) - [ES2017](https://github.com/estree/estree/blob/master/es2017.md) - [ES2018](https://github.com/estree/estree/blob/master/es2018.md) - [ES2019](https://github.com/estree/estree/blob/master/es2019.md) - [ES2020](https://github.com/estree/estree/blob/master/es2020.md) - [ES2021](https://github.com/estree/estree/blob/master/es2021.md) - [ES2022](https://github.com/estree/estree/blob/master/es2022.md) - ES2023 - ES2024 - [ES2025](https://github.com/estree/estree/blob/master/es2025.md) ### const customizedCloneFunctionWithAllowList = espurify.cloneWithAllowlist(allowList) Returns customized function for cloning AST, with user-provided `allowList`. (note: `espurify.cloneWithWhitelist` is still exported but deprecated in favor of more inclusive language and will be removed in future major releases) ### const purifiedAstClone = customizedCloneFunctionWithAllowList(originalAst) Returns new clone of `originalAst` by customized function. #### allowList | type | default value | |:---------|:--------------| | `object` | N/A | `allowList` 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'], ... ``` ### const customizedCloneFunction = espurify.customize(options) Returns customized function for cloning AST, configured by custom `options`. ### const 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.ecmaVersion | type | default value | |:---------------------|:--------------| | `string` or `number` | `2025` | Indicates the ECMAScript version to clone. Must be either 5, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025. #### 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 const espurify = require('espurify'); const estraverse = require('estraverse'); const acorn = require('acorn'); const syntax = estraverse.Syntax; const assert = require('assert'); const jsCode = 'assert("foo")'; // Adding extra informations to AST const originalAst = acorn.parse(jsCode, { locations: true, ranges: true, ecmaVersion: 2022 }); 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 const purifiedClone = espurify.purifyAst(originalAst); // 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' } ], optional: false } } ], sourceType: 'script' }); // original AST is not modified assert.deepEqual(originalAst,{ type: 'Program', start: 0, end: 13, loc: { start: { line: 1, column: 0 }, end: { line: 1, column: 13 } }, range: [ 0, 13 ], body: [ { type: 'ExpressionStatement', start: 0, end: 13, loc: { start: { line: 1, column: 0 }, end: { line: 1, column: 13 } }, range: [ 0, 13 ], expression: { type: 'CallExpression', start: 0, end: 13, loc: { start: { line: 1, column: 0 }, end: { line: 1, column: 13 } }, range: [ 0, 13 ], callee: { type: 'Identifier', start: 0, end: 6, loc: { start: { line: 1, column: 0 }, end: { line: 1, column: 6 } }, range: [ 0, 6 ], name: 'assert' }, arguments: [ { type: 'Literal', start: 7, end: 12, loc: { start: { line: 1, column: 7 }, end: { line: 1, column: 12 } }, range: [ 7, 12 ], value: 'foo', raw: '"foo"', "x-verbatim-bar": { content: '"foo"', precedence: 18 } } ], optional: false } } ], sourceType: 'script' }); ``` INSTALL --------------------------------------- ### via npm Install $ npm install --save espurify Use ```javascript const espurify = require('espurify'); ``` AUTHOR --------------------------------------- * [Takuto Wada](https://github.com/twada) CONTRIBUTORS --------------------------------------- * [Renée Kooi](https://github.com/goto-bus-stop) * [Andreas Lind](https://github.com/papandreou) LICENSE --------------------------------------- Licensed under the [MIT](https://github.com/estools/espurify/blob/master/MIT-LICENSE.txt) license. [npm-url]: https://npmjs.org/package/espurify [npm-image]: https://badge.fury.io/js/espurify.svg [ci-image]: https://github.com/estools/espurify/workflows/Node.js%20CI/badge.svg [ci-url]: https://github.com/estools/espurify/actions?query=workflow%3A%22Node.js+CI%22 [style-url]: https://github.com/Flet/semistandard [style-image]: https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg [license-url]: https://github.com/estools/espurify/blob/master/MIT-LICENSE.txt [license-image]: https://img.shields.io/badge/license-MIT-brightgreen.svg --- _Source: https://npm.io/package/espurify · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._