JarCastingespurify
Clone new AST without extra properties
API
var purifiedAstClone = espurify(originalAst)
Returns new clone of originalAst but without extra properties.
Leaves properties defined in The ESTree Spec (formerly known as Mozilla SpiderMonkey Parser API) only. Also note that extra informations (such as loc, range and raw) are eliminated too.
Supported ECMAScript versions
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.
{
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
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');
AUTHOR
CONTRIBUTORS
LICENSE
Licensed under the MIT license.
