Package Exports

@buxlabs/ast

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 (@buxlabs/ast) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

AbstractSyntaxTree

You might find the class useful if you want to abstract away some ast manipulations such as adding, removing, replacing the nodes and others. The test folder is a good starting point for examples of usage. PRs are highly welcome.

Installation

npm install @buxlabs/ast

Methods

has

Check if ast contains a node of given type.

var source = 'var a = "x";'
var ast = new AbstractSyntaxTree(source)
ast.has('VariableDeclaration')

count

Count ast nodes of given type.

var source = 'var a = "x"; var b = "y";'
var ast = new AbstractSyntaxTree(source)
ast.count('VariableDeclaration')

find

Find all nodes of given type.

var source = 'var a = "x";'
var ast = new AbstractSyntaxTree(source)
ast.find('VariableDeclaration')

each

Iterate over all nodes of given type.

var source = 'var a = "x";'
var ast = new AbstractSyntaxTree(source)
ast.each('VariableDeclaration', node => {
  console.log(node)
})

first

First first node of given type.

var source = 'var a = "x";'
var ast = new AbstractSyntaxTree(source)
ast.first('VariableDeclaration')

last

Find last node of given type.

var source = 'var a = "x";'
var ast = new AbstractSyntaxTree(source)
ast.last('VariableDeclaration')

remove

Remove all nodes that match the criteria.

var source = '"use strict"; var b = 4;'
var ast = new AbstractSyntaxTree(source)
ast.remove({ type: 'Literal', value: 'use strict' })

var source = 'function hello () { var foo = "bar"; return "world"; }'
var ast = new AbstractSyntaxTree(source)
ast.remove('BlockStatement > VariableDeclaration')

walk

Walks over all nodes

var source = 'var a = 1'
var ast = new AbstractSyntaxTree(source)
ast.walk((node, parent) => {
  console.log(node, parent) 
})

traverse

Walks over all nodes

var source = 'var a = 1'
var ast = new AbstractSyntaxTree(source)
ast.walk({
  enter (node) {
    console.log(node)
  },
  leave (node) {
    console.log(node)
  }
})

replace

Replace all nodes that match the criteria.

var source = 'var a = 1'
var ast = new AbstractSyntaxTree(source)
ast.replace({
  enter (node) {
    if (node.type === 'VariableDeclaration') {
      node.kind = 'let'
    }
    return node
  }
})

prepend

Prepend a node to the body.

var source = 'var a = 1;'
var ast = new AbstractSyntaxTree(source)
ast.prepend({
  type: 'ExpressionStatement',
  expression: {
    type: 'Literal',
    value: 'use strict'
  }
})

append

Append a node to the body.

var source = 'var a = 1;'
var ast = new AbstractSyntaxTree(source)
ast.append({
  type: 'ExpressionStatement',
  expression: {
    type: 'Literal',
    value: 'test'
  }
})

wrap

Wrap body with given node.

var source = 'var a = 1;'
var ast = new AbstractSyntaxTree(source)
ast.wrap(body => {
    return [
      {
        "type": "ExpressionStatement",
        "expression": {
          "type": "CallExpression",
          "callee": {
            "type": "FunctionExpression",
            "id": null,
            "params": [],
            "defaults": [],
            "body": {
              "type": "BlockStatement",
              "body": body
            },
            "rest": null,
            "generator": false,
            "expression": false
          },
          "arguments": []
        }
      }
    ]
})

unwrap

Change the code to the first BlockStatement body

var source = '(function () { console.log(1); }())'
var ast = new AbstractSyntaxTree(source)
ast.unwrap()
ast.toSource()

template

Create ast partials from templates

var source = 'console.log(1);'
var ast = new AbstractSyntaxTree(source)
ast.template('var foo = <%= bar %>;' { bar: { type: 'Literal', value: 1 } })

toSource

Convert the ast to string.

var source = 'var a = 1;'
var ast = new AbstractSyntaxTree(source)
var source = ast.toSource()
console.log(source)

var source = 'var a = 1;'
var ast = new AbstractSyntaxTree(source)
var { source, map } = ast.toSource({ sourceMap: true })
console.log(source)
console.log(map)

toSourceMap

Generates a source map.

var source = 'var a = 1;'
var ast = new AbstractSyntaxTree(source)
var map = ast.toSourceMap()
console.log(map)