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// AST walker module for ESTree 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 ESTree node types | |
// can be used to identify node types, as well as Expression and | |
// Statement, 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, baseVisitor, state, override) { | |
if (!baseVisitor) { baseVisitor = base | |
; }(function c(node, st, override) { | |
var type = override || node.type; | |
baseVisitor[type](node, st, c); | |
if (visitors[type]) { visitors[type](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, baseVisitor, state, override) { | |
var ancestors = []; | |
if (!baseVisitor) { baseVisitor = base | |
; }(function c(node, st, override) { | |
var type = override || node.type; | |
var isNew = node !== ancestors[ancestors.length - 1]; | |
if (isNew) { ancestors.push(node); } | |
baseVisitor[type](node, st, c); | |
if (visitors[type]) { visitors[type](node, st || ancestors, ancestors); } | |
if (isNew) { ancestors.pop(); } | |
})(node, state, override); | |
} | |
// 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, baseVisitor, override) { | |
var visitor = funcs ? make(funcs, baseVisitor || undefined) : baseVisitor | |
;(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; }; | |
// A full walk triggers the callback on each node | |
function full(node, callback, baseVisitor, state, override) { | |
if (!baseVisitor) { baseVisitor = base; } | |
var last | |
;(function c(node, st, override) { | |
var type = override || node.type; | |
baseVisitor[type](node, st, c); | |
if (last !== node) { | |
callback(node, st, type); | |
last = node; | |
} | |
})(node, state, override); | |
} | |
// An fullAncestor walk is like an ancestor walk, but triggers | |
// the callback on each node | |
function fullAncestor(node, callback, baseVisitor, state) { | |
if (!baseVisitor) { baseVisitor = base; } | |
var ancestors = [], last | |
;(function c(node, st, override) { | |
var type = override || node.type; | |
var isNew = node !== ancestors[ancestors.length - 1]; | |
if (isNew) { ancestors.push(node); } | |
baseVisitor[type](node, st, c); | |
if (last !== node) { | |
callback(node, st || ancestors, ancestors, type); | |
last = node; | |
} | |
if (isNew) { ancestors.pop(); } | |
})(node, 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, baseVisitor, state) { | |
if (!baseVisitor) { baseVisitor = base; } | |
test = makeTest(test); | |
try { | |
(function c(node, st, override) { | |
var type = override || node.type; | |
if ((start == null || node.start <= start) && | |
(end == null || node.end >= end)) | |
{ baseVisitor[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, baseVisitor, state) { | |
test = makeTest(test); | |
if (!baseVisitor) { baseVisitor = base; } | |
try { | |
(function c(node, st, override) { | |
var type = override || node.type; | |
if (node.start > pos || node.end < pos) { return } | |
baseVisitor[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, baseVisitor, state) { | |
test = makeTest(test); | |
if (!baseVisitor) { baseVisitor = 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) } | |
baseVisitor[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, baseVisitor, state) { | |
test = makeTest(test); | |
if (!baseVisitor) { baseVisitor = 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); } | |
baseVisitor[type](node, st, c); | |
})(node, state); | |
return max | |
} | |
// Used to create a custom walker. Will fill in all missing node | |
// type properties with the defaults. | |
function make(funcs, baseVisitor) { | |
var visitor = Object.create(baseVisitor || 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 = base.StaticBlock = function (node, st, c) { | |
for (var i = 0, list = node.body; i < list.length; i += 1) | |
{ | |
var stmt = list[i]; | |
c(stmt, st, "Statement"); | |
} | |
}; | |
base.Statement = skipThrough; | |
base.EmptyStatement = ignore; | |
base.ExpressionStatement = base.ParenthesizedExpression = base.ChainExpression = | |
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$1 = 0, list$1 = node.cases; i$1 < list$1.length; i$1 += 1) { | |
var cs = list$1[i$1]; | |
if (cs.test) { c(cs.test, st, "Expression"); } | |
for (var i = 0, list = cs.consequent; i < list.length; i += 1) | |
{ | |
var cons = list[i]; | |
c(cons, st, "Statement"); | |
} | |
} | |
}; | |
base.SwitchCase = function (node, st, c) { | |
if (node.test) { c(node.test, st, "Expression"); } | |
for (var i = 0, list = node.consequent; i < list.length; i += 1) | |
{ | |
var cons = list[i]; | |
c(cons, 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) { | |
if (node.param) { c(node.param, st, "Pattern"); } | |
c(node.body, st, "Statement"); | |
}; | |
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, list = node.declarations; i < list.length; i += 1) | |
{ | |
var decl = list[i]; | |
c(decl, 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, list = node.params; i < list.length; i += 1) | |
{ | |
var param = list[i]; | |
c(param, st, "Pattern"); | |
} | |
c(node.body, st, node.expression ? "Expression" : "Statement"); | |
}; | |
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, list = node.elements; i < list.length; i += 1) { | |
var elt = list[i]; | |
if (elt) { c(elt, st, "Pattern"); } | |
} | |
}; | |
base.ObjectPattern = function (node, st, c) { | |
for (var i = 0, list = node.properties; i < list.length; i += 1) { | |
var prop = list[i]; | |
if (prop.type === "Property") { | |
if (prop.computed) { c(prop.key, st, "Expression"); } | |
c(prop.value, st, "Pattern"); | |
} else if (prop.type === "RestElement") { | |
c(prop.argument, st, "Pattern"); | |
} | |
} | |
}; | |
base.Expression = skipThrough; | |
base.ThisExpression = base.Super = base.MetaProperty = ignore; | |
base.ArrayExpression = function (node, st, c) { | |
for (var i = 0, list = node.elements; i < list.length; i += 1) { | |
var elt = list[i]; | |
if (elt) { c(elt, st, "Expression"); } | |
} | |
}; | |
base.ObjectExpression = function (node, st, c) { | |
for (var i = 0, list = node.properties; i < list.length; i += 1) | |
{ | |
var prop = list[i]; | |
c(prop, st); | |
} | |
}; | |
base.FunctionExpression = base.ArrowFunctionExpression = base.FunctionDeclaration; | |
base.SequenceExpression = function (node, st, c) { | |
for (var i = 0, list = node.expressions; i < list.length; i += 1) | |
{ | |
var expr = list[i]; | |
c(expr, st, "Expression"); | |
} | |
}; | |
base.TemplateLiteral = function (node, st, c) { | |
for (var i = 0, list = node.quasis; i < list.length; i += 1) | |
{ | |
var quasi = list[i]; | |
c(quasi, st); | |
} | |
for (var i$1 = 0, list$1 = node.expressions; i$1 < list$1.length; i$1 += 1) | |
{ | |
var expr = list$1[i$1]; | |
c(expr, st, "Expression"); | |
} | |
}; | |
base.TemplateElement = ignore; | |
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, list = node.arguments; i < list.length; i += 1) | |
{ | |
var arg = list[i]; | |
c(arg, 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) { | |
if (node.exported) | |
{ c(node.exported, st); } | |
c(node.source, st, "Expression"); | |
}; | |
base.ImportDeclaration = function (node, st, c) { | |
for (var i = 0, list = node.specifiers; i < list.length; i += 1) | |
{ | |
var spec = list[i]; | |
c(spec, st); | |
} | |
c(node.source, st, "Expression"); | |
}; | |
base.ImportExpression = function (node, st, c) { | |
c(node.source, st, "Expression"); | |
}; | |
base.ImportSpecifier = base.ImportDefaultSpecifier = base.ImportNamespaceSpecifier = base.Identifier = base.PrivateIdentifier = base.Literal = ignore; | |
base.TaggedTemplateExpression = function (node, st, c) { | |
c(node.tag, st, "Expression"); | |
c(node.quasi, st, "Expression"); | |
}; | |
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"); } | |
c(node.body, st); | |
}; | |
base.ClassBody = function (node, st, c) { | |
for (var i = 0, list = node.body; i < list.length; i += 1) | |
{ | |
var elt = list[i]; | |
c(elt, st); | |
} | |
}; | |
base.MethodDefinition = base.PropertyDefinition = base.Property = function (node, st, c) { | |
if (node.computed) { c(node.key, st, "Expression"); } | |
if (node.value) { c(node.value, st, "Expression"); } | |
}; | |
export { ancestor, base, findNodeAfter, findNodeAround, findNodeAt, findNodeBefore, full, fullAncestor, make, recursive, simple }; | |