walk.js 15 KB

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  1. (function (global, factory) {
  2. typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  3. typeof define === 'function' && define.amd ? define(['exports'], factory) :
  4. (global = typeof globalThis !== 'undefined' ? globalThis : global || self, factory((global.acorn = global.acorn || {}, global.acorn.walk = {})));
  5. })(this, (function (exports) { 'use strict';
  6. // AST walker module for ESTree compatible trees
  7. // A simple walk is one where you simply specify callbacks to be
  8. // called on specific nodes. The last two arguments are optional. A
  9. // simple use would be
  10. //
  11. // walk.simple(myTree, {
  12. // Expression: function(node) { ... }
  13. // });
  14. //
  15. // to do something with all expressions. All ESTree node types
  16. // can be used to identify node types, as well as Expression and
  17. // Statement, which denote categories of nodes.
  18. //
  19. // The base argument can be used to pass a custom (recursive)
  20. // walker, and state can be used to give this walked an initial
  21. // state.
  22. function simple(node, visitors, baseVisitor, state, override) {
  23. if (!baseVisitor) { baseVisitor = base
  24. ; }(function c(node, st, override) {
  25. var type = override || node.type;
  26. baseVisitor[type](node, st, c);
  27. if (visitors[type]) { visitors[type](node, st); }
  28. })(node, state, override);
  29. }
  30. // An ancestor walk keeps an array of ancestor nodes (including the
  31. // current node) and passes them to the callback as third parameter
  32. // (and also as state parameter when no other state is present).
  33. function ancestor(node, visitors, baseVisitor, state, override) {
  34. var ancestors = [];
  35. if (!baseVisitor) { baseVisitor = base
  36. ; }(function c(node, st, override) {
  37. var type = override || node.type;
  38. var isNew = node !== ancestors[ancestors.length - 1];
  39. if (isNew) { ancestors.push(node); }
  40. baseVisitor[type](node, st, c);
  41. if (visitors[type]) { visitors[type](node, st || ancestors, ancestors); }
  42. if (isNew) { ancestors.pop(); }
  43. })(node, state, override);
  44. }
  45. // A recursive walk is one where your functions override the default
  46. // walkers. They can modify and replace the state parameter that's
  47. // threaded through the walk, and can opt how and whether to walk
  48. // their child nodes (by calling their third argument on these
  49. // nodes).
  50. function recursive(node, state, funcs, baseVisitor, override) {
  51. var visitor = funcs ? make(funcs, baseVisitor || undefined) : baseVisitor
  52. ;(function c(node, st, override) {
  53. visitor[override || node.type](node, st, c);
  54. })(node, state, override);
  55. }
  56. function makeTest(test) {
  57. if (typeof test === "string")
  58. { return function (type) { return type === test; } }
  59. else if (!test)
  60. { return function () { return true; } }
  61. else
  62. { return test }
  63. }
  64. var Found = function Found(node, state) { this.node = node; this.state = state; };
  65. // A full walk triggers the callback on each node
  66. function full(node, callback, baseVisitor, state, override) {
  67. if (!baseVisitor) { baseVisitor = base; }
  68. var last
  69. ;(function c(node, st, override) {
  70. var type = override || node.type;
  71. baseVisitor[type](node, st, c);
  72. if (last !== node) {
  73. callback(node, st, type);
  74. last = node;
  75. }
  76. })(node, state, override);
  77. }
  78. // An fullAncestor walk is like an ancestor walk, but triggers
  79. // the callback on each node
  80. function fullAncestor(node, callback, baseVisitor, state) {
  81. if (!baseVisitor) { baseVisitor = base; }
  82. var ancestors = [], last
  83. ;(function c(node, st, override) {
  84. var type = override || node.type;
  85. var isNew = node !== ancestors[ancestors.length - 1];
  86. if (isNew) { ancestors.push(node); }
  87. baseVisitor[type](node, st, c);
  88. if (last !== node) {
  89. callback(node, st || ancestors, ancestors, type);
  90. last = node;
  91. }
  92. if (isNew) { ancestors.pop(); }
  93. })(node, state);
  94. }
  95. // Find a node with a given start, end, and type (all are optional,
  96. // null can be used as wildcard). Returns a {node, state} object, or
  97. // undefined when it doesn't find a matching node.
  98. function findNodeAt(node, start, end, test, baseVisitor, state) {
  99. if (!baseVisitor) { baseVisitor = base; }
  100. test = makeTest(test);
  101. try {
  102. (function c(node, st, override) {
  103. var type = override || node.type;
  104. if ((start == null || node.start <= start) &&
  105. (end == null || node.end >= end))
  106. { baseVisitor[type](node, st, c); }
  107. if ((start == null || node.start === start) &&
  108. (end == null || node.end === end) &&
  109. test(type, node))
  110. { throw new Found(node, st) }
  111. })(node, state);
  112. } catch (e) {
  113. if (e instanceof Found) { return e }
  114. throw e
  115. }
  116. }
  117. // Find the innermost node of a given type that contains the given
  118. // position. Interface similar to findNodeAt.
  119. function findNodeAround(node, pos, test, baseVisitor, state) {
  120. test = makeTest(test);
  121. if (!baseVisitor) { baseVisitor = base; }
  122. try {
  123. (function c(node, st, override) {
  124. var type = override || node.type;
  125. if (node.start > pos || node.end < pos) { return }
  126. baseVisitor[type](node, st, c);
  127. if (test(type, node)) { throw new Found(node, st) }
  128. })(node, state);
  129. } catch (e) {
  130. if (e instanceof Found) { return e }
  131. throw e
  132. }
  133. }
  134. // Find the outermost matching node after a given position.
  135. function findNodeAfter(node, pos, test, baseVisitor, state) {
  136. test = makeTest(test);
  137. if (!baseVisitor) { baseVisitor = base; }
  138. try {
  139. (function c(node, st, override) {
  140. if (node.end < pos) { return }
  141. var type = override || node.type;
  142. if (node.start >= pos && test(type, node)) { throw new Found(node, st) }
  143. baseVisitor[type](node, st, c);
  144. })(node, state);
  145. } catch (e) {
  146. if (e instanceof Found) { return e }
  147. throw e
  148. }
  149. }
  150. // Find the outermost matching node before a given position.
  151. function findNodeBefore(node, pos, test, baseVisitor, state) {
  152. test = makeTest(test);
  153. if (!baseVisitor) { baseVisitor = base; }
  154. var max
  155. ;(function c(node, st, override) {
  156. if (node.start > pos) { return }
  157. var type = override || node.type;
  158. if (node.end <= pos && (!max || max.node.end < node.end) && test(type, node))
  159. { max = new Found(node, st); }
  160. baseVisitor[type](node, st, c);
  161. })(node, state);
  162. return max
  163. }
  164. // Used to create a custom walker. Will fill in all missing node
  165. // type properties with the defaults.
  166. function make(funcs, baseVisitor) {
  167. var visitor = Object.create(baseVisitor || base);
  168. for (var type in funcs) { visitor[type] = funcs[type]; }
  169. return visitor
  170. }
  171. function skipThrough(node, st, c) { c(node, st); }
  172. function ignore(_node, _st, _c) {}
  173. // Node walkers.
  174. var base = {};
  175. base.Program = base.BlockStatement = base.StaticBlock = function (node, st, c) {
  176. for (var i = 0, list = node.body; i < list.length; i += 1)
  177. {
  178. var stmt = list[i];
  179. c(stmt, st, "Statement");
  180. }
  181. };
  182. base.Statement = skipThrough;
  183. base.EmptyStatement = ignore;
  184. base.ExpressionStatement = base.ParenthesizedExpression = base.ChainExpression =
  185. function (node, st, c) { return c(node.expression, st, "Expression"); };
  186. base.IfStatement = function (node, st, c) {
  187. c(node.test, st, "Expression");
  188. c(node.consequent, st, "Statement");
  189. if (node.alternate) { c(node.alternate, st, "Statement"); }
  190. };
  191. base.LabeledStatement = function (node, st, c) { return c(node.body, st, "Statement"); };
  192. base.BreakStatement = base.ContinueStatement = ignore;
  193. base.WithStatement = function (node, st, c) {
  194. c(node.object, st, "Expression");
  195. c(node.body, st, "Statement");
  196. };
  197. base.SwitchStatement = function (node, st, c) {
  198. c(node.discriminant, st, "Expression");
  199. for (var i = 0, list = node.cases; i < list.length; i += 1) {
  200. var cs = list[i];
  201. c(cs, st);
  202. }
  203. };
  204. base.SwitchCase = function (node, st, c) {
  205. if (node.test) { c(node.test, st, "Expression"); }
  206. for (var i = 0, list = node.consequent; i < list.length; i += 1)
  207. {
  208. var cons = list[i];
  209. c(cons, st, "Statement");
  210. }
  211. };
  212. base.ReturnStatement = base.YieldExpression = base.AwaitExpression = function (node, st, c) {
  213. if (node.argument) { c(node.argument, st, "Expression"); }
  214. };
  215. base.ThrowStatement = base.SpreadElement =
  216. function (node, st, c) { return c(node.argument, st, "Expression"); };
  217. base.TryStatement = function (node, st, c) {
  218. c(node.block, st, "Statement");
  219. if (node.handler) { c(node.handler, st); }
  220. if (node.finalizer) { c(node.finalizer, st, "Statement"); }
  221. };
  222. base.CatchClause = function (node, st, c) {
  223. if (node.param) { c(node.param, st, "Pattern"); }
  224. c(node.body, st, "Statement");
  225. };
  226. base.WhileStatement = base.DoWhileStatement = function (node, st, c) {
  227. c(node.test, st, "Expression");
  228. c(node.body, st, "Statement");
  229. };
  230. base.ForStatement = function (node, st, c) {
  231. if (node.init) { c(node.init, st, "ForInit"); }
  232. if (node.test) { c(node.test, st, "Expression"); }
  233. if (node.update) { c(node.update, st, "Expression"); }
  234. c(node.body, st, "Statement");
  235. };
  236. base.ForInStatement = base.ForOfStatement = function (node, st, c) {
  237. c(node.left, st, "ForInit");
  238. c(node.right, st, "Expression");
  239. c(node.body, st, "Statement");
  240. };
  241. base.ForInit = function (node, st, c) {
  242. if (node.type === "VariableDeclaration") { c(node, st); }
  243. else { c(node, st, "Expression"); }
  244. };
  245. base.DebuggerStatement = ignore;
  246. base.FunctionDeclaration = function (node, st, c) { return c(node, st, "Function"); };
  247. base.VariableDeclaration = function (node, st, c) {
  248. for (var i = 0, list = node.declarations; i < list.length; i += 1)
  249. {
  250. var decl = list[i];
  251. c(decl, st);
  252. }
  253. };
  254. base.VariableDeclarator = function (node, st, c) {
  255. c(node.id, st, "Pattern");
  256. if (node.init) { c(node.init, st, "Expression"); }
  257. };
  258. base.Function = function (node, st, c) {
  259. if (node.id) { c(node.id, st, "Pattern"); }
  260. for (var i = 0, list = node.params; i < list.length; i += 1)
  261. {
  262. var param = list[i];
  263. c(param, st, "Pattern");
  264. }
  265. c(node.body, st, node.expression ? "Expression" : "Statement");
  266. };
  267. base.Pattern = function (node, st, c) {
  268. if (node.type === "Identifier")
  269. { c(node, st, "VariablePattern"); }
  270. else if (node.type === "MemberExpression")
  271. { c(node, st, "MemberPattern"); }
  272. else
  273. { c(node, st); }
  274. };
  275. base.VariablePattern = ignore;
  276. base.MemberPattern = skipThrough;
  277. base.RestElement = function (node, st, c) { return c(node.argument, st, "Pattern"); };
  278. base.ArrayPattern = function (node, st, c) {
  279. for (var i = 0, list = node.elements; i < list.length; i += 1) {
  280. var elt = list[i];
  281. if (elt) { c(elt, st, "Pattern"); }
  282. }
  283. };
  284. base.ObjectPattern = function (node, st, c) {
  285. for (var i = 0, list = node.properties; i < list.length; i += 1) {
  286. var prop = list[i];
  287. if (prop.type === "Property") {
  288. if (prop.computed) { c(prop.key, st, "Expression"); }
  289. c(prop.value, st, "Pattern");
  290. } else if (prop.type === "RestElement") {
  291. c(prop.argument, st, "Pattern");
  292. }
  293. }
  294. };
  295. base.Expression = skipThrough;
  296. base.ThisExpression = base.Super = base.MetaProperty = ignore;
  297. base.ArrayExpression = function (node, st, c) {
  298. for (var i = 0, list = node.elements; i < list.length; i += 1) {
  299. var elt = list[i];
  300. if (elt) { c(elt, st, "Expression"); }
  301. }
  302. };
  303. base.ObjectExpression = function (node, st, c) {
  304. for (var i = 0, list = node.properties; i < list.length; i += 1)
  305. {
  306. var prop = list[i];
  307. c(prop, st);
  308. }
  309. };
  310. base.FunctionExpression = base.ArrowFunctionExpression = base.FunctionDeclaration;
  311. base.SequenceExpression = function (node, st, c) {
  312. for (var i = 0, list = node.expressions; i < list.length; i += 1)
  313. {
  314. var expr = list[i];
  315. c(expr, st, "Expression");
  316. }
  317. };
  318. base.TemplateLiteral = function (node, st, c) {
  319. for (var i = 0, list = node.quasis; i < list.length; i += 1)
  320. {
  321. var quasi = list[i];
  322. c(quasi, st);
  323. }
  324. for (var i$1 = 0, list$1 = node.expressions; i$1 < list$1.length; i$1 += 1)
  325. {
  326. var expr = list$1[i$1];
  327. c(expr, st, "Expression");
  328. }
  329. };
  330. base.TemplateElement = ignore;
  331. base.UnaryExpression = base.UpdateExpression = function (node, st, c) {
  332. c(node.argument, st, "Expression");
  333. };
  334. base.BinaryExpression = base.LogicalExpression = function (node, st, c) {
  335. c(node.left, st, "Expression");
  336. c(node.right, st, "Expression");
  337. };
  338. base.AssignmentExpression = base.AssignmentPattern = function (node, st, c) {
  339. c(node.left, st, "Pattern");
  340. c(node.right, st, "Expression");
  341. };
  342. base.ConditionalExpression = function (node, st, c) {
  343. c(node.test, st, "Expression");
  344. c(node.consequent, st, "Expression");
  345. c(node.alternate, st, "Expression");
  346. };
  347. base.NewExpression = base.CallExpression = function (node, st, c) {
  348. c(node.callee, st, "Expression");
  349. if (node.arguments)
  350. { for (var i = 0, list = node.arguments; i < list.length; i += 1)
  351. {
  352. var arg = list[i];
  353. c(arg, st, "Expression");
  354. } }
  355. };
  356. base.MemberExpression = function (node, st, c) {
  357. c(node.object, st, "Expression");
  358. if (node.computed) { c(node.property, st, "Expression"); }
  359. };
  360. base.ExportNamedDeclaration = base.ExportDefaultDeclaration = function (node, st, c) {
  361. if (node.declaration)
  362. { c(node.declaration, st, node.type === "ExportNamedDeclaration" || node.declaration.id ? "Statement" : "Expression"); }
  363. if (node.source) { c(node.source, st, "Expression"); }
  364. };
  365. base.ExportAllDeclaration = function (node, st, c) {
  366. if (node.exported)
  367. { c(node.exported, st); }
  368. c(node.source, st, "Expression");
  369. };
  370. base.ImportDeclaration = function (node, st, c) {
  371. for (var i = 0, list = node.specifiers; i < list.length; i += 1)
  372. {
  373. var spec = list[i];
  374. c(spec, st);
  375. }
  376. c(node.source, st, "Expression");
  377. };
  378. base.ImportExpression = function (node, st, c) {
  379. c(node.source, st, "Expression");
  380. };
  381. base.ImportSpecifier = base.ImportDefaultSpecifier = base.ImportNamespaceSpecifier = base.Identifier = base.PrivateIdentifier = base.Literal = ignore;
  382. base.TaggedTemplateExpression = function (node, st, c) {
  383. c(node.tag, st, "Expression");
  384. c(node.quasi, st, "Expression");
  385. };
  386. base.ClassDeclaration = base.ClassExpression = function (node, st, c) { return c(node, st, "Class"); };
  387. base.Class = function (node, st, c) {
  388. if (node.id) { c(node.id, st, "Pattern"); }
  389. if (node.superClass) { c(node.superClass, st, "Expression"); }
  390. c(node.body, st);
  391. };
  392. base.ClassBody = function (node, st, c) {
  393. for (var i = 0, list = node.body; i < list.length; i += 1)
  394. {
  395. var elt = list[i];
  396. c(elt, st);
  397. }
  398. };
  399. base.MethodDefinition = base.PropertyDefinition = base.Property = function (node, st, c) {
  400. if (node.computed) { c(node.key, st, "Expression"); }
  401. if (node.value) { c(node.value, st, "Expression"); }
  402. };
  403. exports.ancestor = ancestor;
  404. exports.base = base;
  405. exports.findNodeAfter = findNodeAfter;
  406. exports.findNodeAround = findNodeAround;
  407. exports.findNodeAt = findNodeAt;
  408. exports.findNodeBefore = findNodeBefore;
  409. exports.full = full;
  410. exports.fullAncestor = fullAncestor;
  411. exports.make = make;
  412. exports.recursive = recursive;
  413. exports.simple = simple;
  414. }));