(function (global, factory) {

typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
typeof define === 'function' && define.amd ? define(['exports'], factory) :
(factory((global.acorn = global.acorn || {}, global.acorn.walk = global.acorn.walk || {})));

}(this, (function (exports) { 'use strict';

// AST walker module for Mozilla Parser API compatible trees

// A simple walk is one where you simply specify callbacks to be // called on specific nodes. The last two arguments are optional. A // simple use would be // // walk.simple(myTree, { // Expression: function(node) { … } // }); // // to do something with all expressions. All Parser API node types // can be used to identify node types, as well as Expression, // Statement, and ScopeBody, which denote categories of nodes. // // The base argument can be used to pass a custom (recursive) // walker, and state can be used to give this walked an initial // state.

function simple(node, visitors, base, state, override) {

if (!base) base = exports.base
;(function c(node, st, override) {
  var type = override || node.type, found = visitors[type]
  base[type](node, st, c)
  if (found) found(node, st)
})(node, state, override)

}

// An ancestor walk keeps an array of ancestor nodes (including the // current node) and passes them to the callback as third parameter // (and also as state parameter when no other state is present). function ancestor(node, visitors, base, state) {

if (!base) base = exports.base
var ancestors = []
;(function c(node, st, override) {
  var type = override || node.type, found = visitors[type]
  var isNew = node != ancestors[ancestors.length - 1]
  if (isNew) ancestors.push(node)
  base[type](node, st, c)
  if (found) found(node, st || ancestors, ancestors)
  if (isNew) ancestors.pop()
})(node, state)

}

// A recursive walk is one where your functions override the default // walkers. They can modify and replace the state parameter that's // threaded through the walk, and can opt how and whether to walk // their child nodes (by calling their third argument on these // nodes). function recursive(node, state, funcs, base, override) {

var visitor = funcs ? exports.make(funcs, base) : base
;(function c(node, st, override) {
  visitor[override || node.type](node, st, c)
})(node, state, override)

}

function makeTest(test) {

if (typeof test == "string")
  return function (type) { return type == test; }
else if (!test)
  return function () { return true; }
else
  return test

}

var Found = function Found(node, state) { this.node = node; this.state = state };

// Find a node with a given start, end, and type (all are optional, // null can be used as wildcard). Returns a {node, state} object, or // undefined when it doesn't find a matching node. function findNodeAt(node, start, end, test, base, state) {

test = makeTest(test)
if (!base) base = exports.base
try {
  ;(function c(node, st, override) {
    var type = override || node.type
    if ((start == null || node.start <= start) &&
        (end == null || node.end >= end))
      base[type](node, st, c)
    if ((start == null || node.start == start) &&
        (end == null || node.end == end) &&
        test(type, node))
      throw new Found(node, st)
  })(node, state)
} catch (e) {
  if (e instanceof Found) return e
  throw e
}

}

// Find the innermost node of a given type that contains the given // position. Interface similar to findNodeAt. function findNodeAround(node, pos, test, base, state) {

test = makeTest(test)
if (!base) base = exports.base
try {
  ;(function c(node, st, override) {
    var type = override || node.type
    if (node.start > pos || node.end < pos) return
    base[type](node, st, c)
    if (test(type, node)) throw new Found(node, st)
  })(node, state)
} catch (e) {
  if (e instanceof Found) return e
  throw e
}

}

// Find the outermost matching node after a given position. function findNodeAfter(node, pos, test, base, state) {

test = makeTest(test)
if (!base) base = exports.base
try {
  ;(function c(node, st, override) {
    if (node.end < pos) return
    var type = override || node.type
    if (node.start >= pos && test(type, node)) throw new Found(node, st)
    base[type](node, st, c)
  })(node, state)
} catch (e) {
  if (e instanceof Found) return e
  throw e
}

}

// Find the outermost matching node before a given position. function findNodeBefore(node, pos, test, base, state) {

test = makeTest(test)
if (!base) base = exports.base
var max
;(function c(node, st, override) {
  if (node.start > pos) return
  var type = override || node.type
  if (node.end <= pos && (!max || max.node.end < node.end) && test(type, node))
    max = new Found(node, st)
  base[type](node, st, c)
})(node, state)
return max

}

// Fallback to an Object.create polyfill for older environments. var create = Object.create || function(proto) {

function Ctor() {}
Ctor.prototype = proto
return new Ctor

}

// Used to create a custom walker. Will fill in all missing node // type properties with the defaults. function make(funcs, base) {

if (!base) base = exports.base
var visitor = create(base)
for (var type in funcs) visitor[type] = funcs[type]
return visitor

}

function skipThrough(node, st, c) { c(node, st) } function ignore(_node, _st, _c) {}

// Node walkers.

var base = {}

base.Program = base.BlockStatement = function (node, st, c) {

for (var i = 0; i < node.body.length; ++i)
  c(node.body[i], st, "Statement")

} base.Statement = skipThrough base.EmptyStatement = ignore base.ExpressionStatement = base.ParenthesizedExpression =

function (node, st, c) { return c(node.expression, st, "Expression"); }

base.IfStatement = function (node, st, c) {

c(node.test, st, "Expression")
c(node.consequent, st, "Statement")
if (node.alternate) c(node.alternate, st, "Statement")

} base.LabeledStatement = function (node, st, c) { return c(node.body, st, “Statement”); } base.BreakStatement = base.ContinueStatement = ignore base.WithStatement = function (node, st, c) {

c(node.object, st, "Expression")
c(node.body, st, "Statement")

} base.SwitchStatement = function (node, st, c) {

c(node.discriminant, st, "Expression")
for (var i = 0; i < node.cases.length; ++i) {
  var cs = node.cases[i]
  if (cs.test) c(cs.test, st, "Expression")
  for (var j = 0; j < cs.consequent.length; ++j)
    c(cs.consequent[j], st, "Statement")
}

} base.ReturnStatement = base.YieldExpression = base.AwaitExpression = function (node, st, c) {

if (node.argument) c(node.argument, st, "Expression")

} base.ThrowStatement = base.SpreadElement =

function (node, st, c) { return c(node.argument, st, "Expression"); }

base.TryStatement = function (node, st, c) {

c(node.block, st, "Statement")
if (node.handler) c(node.handler, st)
if (node.finalizer) c(node.finalizer, st, "Statement")

} base.CatchClause = function (node, st, c) {

c(node.param, st, "Pattern")
c(node.body, st, "ScopeBody")

} base.WhileStatement = base.DoWhileStatement = function (node, st, c) {

c(node.test, st, "Expression")
c(node.body, st, "Statement")

} base.ForStatement = function (node, st, c) {

if (node.init) c(node.init, st, "ForInit")
if (node.test) c(node.test, st, "Expression")
if (node.update) c(node.update, st, "Expression")
c(node.body, st, "Statement")

} base.ForInStatement = base.ForOfStatement = function (node, st, c) {

c(node.left, st, "ForInit")
c(node.right, st, "Expression")
c(node.body, st, "Statement")

} base.ForInit = function (node, st, c) {

if (node.type == "VariableDeclaration") c(node, st)
else c(node, st, "Expression")

} base.DebuggerStatement = ignore

base.FunctionDeclaration = function (node, st, c) { return c(node, st, “Function”); } base.VariableDeclaration = function (node, st, c) {

for (var i = 0; i < node.declarations.length; ++i)
  c(node.declarations[i], st)

} base.VariableDeclarator = function (node, st, c) {

c(node.id, st, "Pattern")
if (node.init) c(node.init, st, "Expression")

}

base.Function = function (node, st, c) {

if (node.id) c(node.id, st, "Pattern")
for (var i = 0; i < node.params.length; i++)
  c(node.params[i], st, "Pattern")
c(node.body, st, node.expression ? "ScopeExpression" : "ScopeBody")

} // FIXME drop these node types in next major version // (They are awkward, and in ES6 every block can be a scope.) base.ScopeBody = function (node, st, c) { return c(node, st, “Statement”); } base.ScopeExpression = function (node, st, c) { return c(node, st, “Expression”); }

base.Pattern = function (node, st, c) {

if (node.type == "Identifier")
  c(node, st, "VariablePattern")
else if (node.type == "MemberExpression")
  c(node, st, "MemberPattern")
else
  c(node, st)

} base.VariablePattern = ignore base.MemberPattern = skipThrough base.RestElement = function (node, st, c) { return c(node.argument, st, “Pattern”); } base.ArrayPattern = function (node, st, c) {

for (var i = 0; i < node.elements.length; ++i) {
  var elt = node.elements[i]
  if (elt) c(elt, st, "Pattern")
}

} base.ObjectPattern = function (node, st, c) {

for (var i = 0; i < node.properties.length; ++i)
  c(node.properties[i].value, st, "Pattern")

}

base.Expression = skipThrough base.ThisExpression = base.Super = base.MetaProperty = ignore base.ArrayExpression = function (node, st, c) {

for (var i = 0; i < node.elements.length; ++i) {
  var elt = node.elements[i]
  if (elt) c(elt, st, "Expression")
}

} base.ObjectExpression = function (node, st, c) {

for (var i = 0; i < node.properties.length; ++i)
  c(node.properties[i], st)

} base.FunctionExpression = base.ArrowFunctionExpression = base.FunctionDeclaration base.SequenceExpression = base.TemplateLiteral = function (node, st, c) {

for (var i = 0; i < node.expressions.length; ++i)
  c(node.expressions[i], st, "Expression")

} base.UnaryExpression = base.UpdateExpression = function (node, st, c) {

c(node.argument, st, "Expression")

} base.BinaryExpression = base.LogicalExpression = function (node, st, c) {

c(node.left, st, "Expression")
c(node.right, st, "Expression")

} base.AssignmentExpression = base.AssignmentPattern = function (node, st, c) {

c(node.left, st, "Pattern")
c(node.right, st, "Expression")

} base.ConditionalExpression = function (node, st, c) {

c(node.test, st, "Expression")
c(node.consequent, st, "Expression")
c(node.alternate, st, "Expression")

} base.NewExpression = base.CallExpression = function (node, st, c) {

c(node.callee, st, "Expression")
if (node.arguments) for (var i = 0; i < node.arguments.length; ++i)
  c(node.arguments[i], st, "Expression")

} base.MemberExpression = function (node, st, c) {

c(node.object, st, "Expression")
if (node.computed) c(node.property, st, "Expression")

} base.ExportNamedDeclaration = base.ExportDefaultDeclaration = function (node, st, c) {

if (node.declaration)
  c(node.declaration, st, node.type == "ExportNamedDeclaration" || node.declaration.id ? "Statement" : "Expression")
if (node.source) c(node.source, st, "Expression")

} base.ExportAllDeclaration = function (node, st, c) {

c(node.source, st, "Expression")

} base.ImportDeclaration = function (node, st, c) {

for (var i = 0; i < node.specifiers.length; i++)
  c(node.specifiers[i], st)
c(node.source, st, "Expression")

} base.ImportSpecifier = base.ImportDefaultSpecifier = base.ImportNamespaceSpecifier = base.Identifier = base.Literal = ignore

base.TaggedTemplateExpression = function (node, st, c) {

c(node.tag, st, "Expression")
c(node.quasi, st)

} base.ClassDeclaration = base.ClassExpression = function (node, st, c) { return c(node, st, “Class”); } base.Class = function (node, st, c) {

if (node.id) c(node.id, st, "Pattern")
if (node.superClass) c(node.superClass, st, "Expression")
for (var i = 0; i < node.body.body.length; i++)
  c(node.body.body[i], st)

} base.MethodDefinition = base.Property = function (node, st, c) {

if (node.computed) c(node.key, st, "Expression")
c(node.value, st, "Expression")

}

exports.simple = simple; exports.ancestor = ancestor; exports.recursive = recursive; exports.findNodeAt = findNodeAt; exports.findNodeAround = findNodeAround; exports.findNodeAfter = findNodeAfter; exports.findNodeBefore = findNodeBefore; exports.make = make; exports.base = base;

Object.defineProperty(exports, '__esModule', { value: true });

})));