260 lines
6.2 KiB
Markdown
260 lines
6.2 KiB
Markdown
espurify
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================================
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Clone new AST without extra properties
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[](https://travis-ci.org/estools/espurify)
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[](https://badge.fury.io/js/espurify)
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[](https://github.com/estools/espurify/blob/master/MIT-LICENSE.txt)
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API
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---------------------------------------
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### var purifiedAstClone = espurify(originalAst)
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Returns new clone of `originalAst` but without extra properties.
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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.
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`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.
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### var customizedCloneFunctionWithWhiteList = espurify.cloneWithWhitelist(whiteList)
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Returns customized function for cloning AST, with user-provided `whiteList`.
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### var purifiedAstClone = customizedCloneFunctionWithWhiteList(originalAst)
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Returns new clone of `originalAst` by customized function.
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#### whiteList
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| type | default value |
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|:---------|:--------------|
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| `object` | N/A |
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`whiteList` is an object containing NodeType as keys and properties as values.
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```js
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{
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ArrayExpression: ['type', 'elements'],
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ArrayPattern: ['type', 'elements'],
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ArrowFunctionExpression: ['type', 'id', 'params', 'body', 'generator', 'expression'],
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AssignmentExpression: ['type', 'operator', 'left', 'right'],
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...
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```
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### var customizedCloneFunction = espurify.customize(options)
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Returns customized function for cloning AST, configured by custom `options`.
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### var purifiedAstClone = customizedCloneFunction(originalAst)
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Returns new clone of `originalAst` by customized function.
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#### options
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| type | default value |
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|:---------|:--------------|
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| `object` | `{}` |
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Configuration options. If not passed, default options will be used.
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#### options.extra
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| type | default value |
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|:--------------------|:--------------|
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| `array` of `string` | null |
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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.
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EXAMPLE
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---------------------------------------
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```javascript
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var espurify = require('espurify'),
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estraverse = require('estraverse'),
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esprima = require('esprima'),
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syntax = estraverse.Syntax,
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assert = require('assert');
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var jsCode = 'assert("foo")';
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// Adding extra informations to AST
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var originalAst = esprima.parse(jsCode, {tolerant: true, loc: true, raw: true});
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estraverse.replace(originalAst, {
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leave: function (currentNode, parentNode) {
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if (currentNode.type === syntax.Literal && typeof currentNode.raw !== 'undefined') {
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currentNode['x-verbatim-bar'] = {
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content : currentNode.raw,
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precedence : 18 // escodegen.Precedence.Primary
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};
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return currentNode;
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} else {
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return undefined;
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}
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}
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});
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// purify AST
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var purifiedClone = espurify(originalAst);
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// original AST is not modified
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assert.deepEqual(originalAst, {
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type: 'Program',
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body: [
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{
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type: 'ExpressionStatement',
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expression: {
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type: 'CallExpression',
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callee: {
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type: 'Identifier',
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name: 'assert',
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loc: {
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start: {
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line: 1,
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column: 0
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},
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end: {
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line: 1,
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column: 6
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}
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}
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},
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arguments: [
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{
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type: 'Literal',
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value: 'foo',
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raw: '"foo"',
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loc: {
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start: {
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line: 1,
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column: 7
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},
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end: {
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line: 1,
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column: 12
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}
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},
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"x-verbatim-bar": {
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content: '"foo"',
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precedence: 18
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}
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}
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],
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loc: {
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start: {
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line: 1,
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column: 0
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},
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end: {
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line: 1,
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column: 13
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}
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}
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},
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loc: {
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start: {
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line: 1,
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column: 0
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},
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end: {
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line: 1,
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column: 13
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}
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}
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}
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],
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loc: {
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start: {
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line: 1,
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column: 0
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},
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end: {
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line: 1,
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column: 13
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}
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},
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errors: []
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});
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// Extra properties are eliminated from cloned AST
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assert.deepEqual(purifiedClone, {
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type: 'Program',
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body: [
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{
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type: 'ExpressionStatement',
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expression: {
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type: 'CallExpression',
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callee: {
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type: 'Identifier',
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name: 'assert'
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},
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arguments: [
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{
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type: 'Literal',
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value: 'foo'
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}
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]
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}
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}
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]
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});
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```
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INSTALL
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---------------------------------------
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### via npm
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Install
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$ npm install --save espurify
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Use
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```javascript
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var espurify = require('espurify');
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```
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#### use espurify module on browser
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`espurify` function is exported
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<script type="text/javascript" src="./path/to/node_modules/espurify/build/espurify.js"></script>
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### via bower
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Install
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$ bower install --save espurify
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Load (`espurify` function is exported)
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<script type="text/javascript" src="./path/to/bower_components/espurify/build/espurify.js"></script>
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AUTHOR
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---------------------------------------
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* [Takuto Wada](https://github.com/twada)
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LICENSE
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---------------------------------------
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Licensed under the [MIT](https://github.com/estools/espurify/blob/master/MIT-LICENSE.txt) license.
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