"use strict"; var __importDefault = (this && this.__importDefault) || function (mod) { return (mod && mod.__esModule) ? mod : { "default": mod }; }; var __importStar = (this && this.__importStar) || function (mod) { if (mod && mod.__esModule) return mod; var result = {}; if (mod != null) for (var k in mod) if (Object.hasOwnProperty.call(mod, k)) result[k] = mod[k]; result["default"] = mod; return result; }; Object.defineProperty(exports, "__esModule", { value: true }); var assert_1 = __importDefault(require("assert")); var types = __importStar(require("ast-types")); var n = types.namedTypes; var isArray = types.builtInTypes.array; var isNumber = types.builtInTypes.number; var util = __importStar(require("./util")); var FastPath = function FastPath(value) { assert_1.default.ok(this instanceof FastPath); this.stack = [value]; }; var FPp = FastPath.prototype; // Static convenience function for coercing a value to a FastPath. FastPath.from = function (obj) { if (obj instanceof FastPath) { // Return a defensive copy of any existing FastPath instances. return obj.copy(); } if (obj instanceof types.NodePath) { // For backwards compatibility, unroll NodePath instances into // lightweight FastPath [..., name, value] stacks. var copy = Object.create(FastPath.prototype); var stack = [obj.value]; for (var pp; (pp = obj.parentPath); obj = pp) stack.push(obj.name, pp.value); copy.stack = stack.reverse(); return copy; } // Otherwise use obj as the value of the new FastPath instance. return new FastPath(obj); }; FPp.copy = function copy() { var copy = Object.create(FastPath.prototype); copy.stack = this.stack.slice(0); return copy; }; // The name of the current property is always the penultimate element of // this.stack, and always a String. FPp.getName = function getName() { var s = this.stack; var len = s.length; if (len > 1) { return s[len - 2]; } // Since the name is always a string, null is a safe sentinel value to // return if we do not know the name of the (root) value. return null; }; // The value of the current property is always the final element of // this.stack. FPp.getValue = function getValue() { var s = this.stack; return s[s.length - 1]; }; FPp.valueIsDuplicate = function () { var s = this.stack; var valueIndex = s.length - 1; return s.lastIndexOf(s[valueIndex], valueIndex - 1) >= 0; }; function getNodeHelper(path, count) { var s = path.stack; for (var i = s.length - 1; i >= 0; i -= 2) { var value = s[i]; if (n.Node.check(value) && --count < 0) { return value; } } return null; } FPp.getNode = function getNode(count) { if (count === void 0) { count = 0; } return getNodeHelper(this, ~~count); }; FPp.getParentNode = function getParentNode(count) { if (count === void 0) { count = 0; } return getNodeHelper(this, ~~count + 1); }; // The length of the stack can be either even or odd, depending on whether // or not we have a name for the root value. The difference between the // index of the root value and the index of the final value is always // even, though, which allows us to return the root value in constant time // (i.e. without iterating backwards through the stack). FPp.getRootValue = function getRootValue() { var s = this.stack; if (s.length % 2 === 0) { return s[1]; } return s[0]; }; // Temporarily push properties named by string arguments given after the // callback function onto this.stack, then call the callback with a // reference to this (modified) FastPath object. Note that the stack will // be restored to its original state after the callback is finished, so it // is probably a mistake to retain a reference to the path. FPp.call = function call(callback /*, name1, name2, ... */) { var s = this.stack; var origLen = s.length; var value = s[origLen - 1]; var argc = arguments.length; for (var i = 1; i < argc; ++i) { var name = arguments[i]; value = value[name]; s.push(name, value); } var result = callback(this); s.length = origLen; return result; }; // Similar to FastPath.prototype.call, except that the value obtained by // accessing this.getValue()[name1][name2]... should be array-like. The // callback will be called with a reference to this path object for each // element of the array. FPp.each = function each(callback /*, name1, name2, ... */) { var s = this.stack; var origLen = s.length; var value = s[origLen - 1]; var argc = arguments.length; for (var i = 1; i < argc; ++i) { var name = arguments[i]; value = value[name]; s.push(name, value); } for (var i = 0; i < value.length; ++i) { if (i in value) { s.push(i, value[i]); // If the callback needs to know the value of i, call // path.getName(), assuming path is the parameter name. callback(this); s.length -= 2; } } s.length = origLen; }; // Similar to FastPath.prototype.each, except that the results of the // callback function invocations are stored in an array and returned at // the end of the iteration. FPp.map = function map(callback /*, name1, name2, ... */) { var s = this.stack; var origLen = s.length; var value = s[origLen - 1]; var argc = arguments.length; for (var i = 1; i < argc; ++i) { var name = arguments[i]; value = value[name]; s.push(name, value); } var result = new Array(value.length); for (var i = 0; i < value.length; ++i) { if (i in value) { s.push(i, value[i]); result[i] = callback(this, i); s.length -= 2; } } s.length = origLen; return result; }; // Returns true if the node at the tip of the path is wrapped with // parentheses, OR if the only reason the node needed parentheses was that // it couldn't be the first expression in the enclosing statement (see // FastPath#canBeFirstInStatement), and it has an opening `(` character. // For example, the FunctionExpression in `(function(){}())` appears to // need parentheses only because it's the first expression in the AST, but // since it happens to be preceded by a `(` (which is not apparent from // the AST but can be determined using FastPath#getPrevToken), there is no // ambiguity about how to parse it, so it counts as having parentheses, // even though it is not immediately followed by a `)`. FPp.hasParens = function () { var node = this.getNode(); var prevToken = this.getPrevToken(node); if (!prevToken) { return false; } var nextToken = this.getNextToken(node); if (!nextToken) { return false; } if (prevToken.value === "(") { if (nextToken.value === ")") { // If the node preceded by a `(` token and followed by a `)` token, // then of course it has parentheses. return true; } // If this is one of the few Expression types that can't come first in // the enclosing statement because of parsing ambiguities (namely, // FunctionExpression, ObjectExpression, and ClassExpression) and // this.firstInStatement() returns true, and the node would not need // parentheses in an expression context because this.needsParens(true) // returns false, then it just needs an opening parenthesis to resolve // the parsing ambiguity that made it appear to need parentheses. var justNeedsOpeningParen = !this.canBeFirstInStatement() && this.firstInStatement() && !this.needsParens(true); if (justNeedsOpeningParen) { return true; } } return false; }; FPp.getPrevToken = function (node) { node = node || this.getNode(); var loc = node && node.loc; var tokens = loc && loc.tokens; if (tokens && loc.start.token > 0) { var token = tokens[loc.start.token - 1]; if (token) { // Do not return tokens that fall outside the root subtree. var rootLoc = this.getRootValue().loc; if (util.comparePos(rootLoc.start, token.loc.start) <= 0) { return token; } } } return null; }; FPp.getNextToken = function (node) { node = node || this.getNode(); var loc = node && node.loc; var tokens = loc && loc.tokens; if (tokens && loc.end.token < tokens.length) { var token = tokens[loc.end.token]; if (token) { // Do not return tokens that fall outside the root subtree. var rootLoc = this.getRootValue().loc; if (util.comparePos(token.loc.end, rootLoc.end) <= 0) { return token; } } } return null; }; // Inspired by require("ast-types").NodePath.prototype.needsParens, but // more efficient because we're iterating backwards through a stack. FPp.needsParens = function (assumeExpressionContext) { var node = this.getNode(); // This needs to come before `if (!parent) { return false }` because // an object destructuring assignment requires parens for // correctness even when it's the topmost expression. if (node.type === "AssignmentExpression" && node.left.type === 'ObjectPattern') { return true; } var parent = this.getParentNode(); if (!parent) { return false; } var name = this.getName(); // If the value of this path is some child of a Node and not a Node // itself, then it doesn't need parentheses. Only Node objects (in fact, // only Expression nodes) need parentheses. if (this.getValue() !== node) { return false; } // Only statements don't need parentheses. if (n.Statement.check(node)) { return false; } // Identifiers never need parentheses. if (node.type === "Identifier") { return false; } if (parent.type === "ParenthesizedExpression") { return false; } switch (node.type) { case "UnaryExpression": case "SpreadElement": case "SpreadProperty": return parent.type === "MemberExpression" && name === "object" && parent.object === node; case "BinaryExpression": case "LogicalExpression": switch (parent.type) { case "CallExpression": return name === "callee" && parent.callee === node; case "UnaryExpression": case "SpreadElement": case "SpreadProperty": return true; case "MemberExpression": return name === "object" && parent.object === node; case "BinaryExpression": case "LogicalExpression": var po = parent.operator; var pp = PRECEDENCE[po]; var no = node.operator; var np = PRECEDENCE[no]; if (pp > np) { return true; } if (pp === np && name === "right") { assert_1.default.strictEqual(parent.right, node); return true; } default: return false; } case "SequenceExpression": switch (parent.type) { case "ReturnStatement": return false; case "ForStatement": // Although parentheses wouldn't hurt around sequence expressions in // the head of for loops, traditional style dictates that e.g. i++, // j++ should not be wrapped with parentheses. return false; case "ExpressionStatement": return name !== "expression"; default: // Otherwise err on the side of overparenthesization, adding // explicit exceptions above if this proves overzealous. return true; } case "YieldExpression": switch (parent.type) { case "BinaryExpression": case "LogicalExpression": case "UnaryExpression": case "SpreadElement": case "SpreadProperty": case "CallExpression": case "MemberExpression": case "NewExpression": case "ConditionalExpression": case "YieldExpression": return true; default: return false; } case "IntersectionTypeAnnotation": case "UnionTypeAnnotation": return parent.type === "NullableTypeAnnotation"; case "Literal": return parent.type === "MemberExpression" && isNumber.check(node.value) && name === "object" && parent.object === node; // Babel 6 Literal split case "NumericLiteral": return parent.type === "MemberExpression" && name === "object" && parent.object === node; case "AssignmentExpression": case "ConditionalExpression": switch (parent.type) { case "UnaryExpression": case "SpreadElement": case "SpreadProperty": case "BinaryExpression": case "LogicalExpression": return true; case "CallExpression": case "NewExpression": return name === "callee" && parent.callee === node; case "ConditionalExpression": return name === "test" && parent.test === node; case "MemberExpression": return name === "object" && parent.object === node; default: return false; } case "ArrowFunctionExpression": if (n.CallExpression.check(parent) && name === 'callee') { return true; } if (n.MemberExpression.check(parent) && name === 'object') { return true; } return isBinary(parent); case "ObjectExpression": if (parent.type === "ArrowFunctionExpression" && name === "body") { return true; } break; case 'TSAsExpression': if (parent.type === 'ArrowFunctionExpression' && name === 'body' && node.expression.type === 'ObjectExpression') { return true; } break; case "CallExpression": if (name === "declaration" && n.ExportDefaultDeclaration.check(parent) && n.FunctionExpression.check(node.callee)) { return true; } } if (parent.type === "NewExpression" && name === "callee" && parent.callee === node) { return containsCallExpression(node); } if (assumeExpressionContext !== true && !this.canBeFirstInStatement() && this.firstInStatement()) { return true; } return false; }; function isBinary(node) { return n.BinaryExpression.check(node) || n.LogicalExpression.check(node); } // @ts-ignore 'isUnaryLike' is declared but its value is never read. [6133] function isUnaryLike(node) { return n.UnaryExpression.check(node) // I considered making SpreadElement and SpreadProperty subtypes of // UnaryExpression, but they're not really Expression nodes. || (n.SpreadElement && n.SpreadElement.check(node)) || (n.SpreadProperty && n.SpreadProperty.check(node)); } var PRECEDENCE = {}; [["||"], ["&&"], ["|"], ["^"], ["&"], ["==", "===", "!=", "!=="], ["<", ">", "<=", ">=", "in", "instanceof"], [">>", "<<", ">>>"], ["+", "-"], ["*", "/", "%"], ["**"] ].forEach(function (tier, i) { tier.forEach(function (op) { PRECEDENCE[op] = i; }); }); function containsCallExpression(node) { if (n.CallExpression.check(node)) { return true; } if (isArray.check(node)) { return node.some(containsCallExpression); } if (n.Node.check(node)) { return types.someField(node, function (_name, child) { return containsCallExpression(child); }); } return false; } FPp.canBeFirstInStatement = function () { var node = this.getNode(); if (n.FunctionExpression.check(node)) { return false; } if (n.ObjectExpression.check(node)) { return false; } if (n.ClassExpression.check(node)) { return false; } return true; }; FPp.firstInStatement = function () { var s = this.stack; var parentName, parent; var childName, child; for (var i = s.length - 1; i >= 0; i -= 2) { if (n.Node.check(s[i])) { childName = parentName; child = parent; parentName = s[i - 1]; parent = s[i]; } if (!parent || !child) { continue; } if (n.BlockStatement.check(parent) && parentName === "body" && childName === 0) { assert_1.default.strictEqual(parent.body[0], child); return true; } if (n.ExpressionStatement.check(parent) && childName === "expression") { assert_1.default.strictEqual(parent.expression, child); return true; } if (n.AssignmentExpression.check(parent) && childName === "left") { assert_1.default.strictEqual(parent.left, child); return true; } if (n.ArrowFunctionExpression.check(parent) && childName === "body") { assert_1.default.strictEqual(parent.body, child); return true; } if (n.SequenceExpression.check(parent) && parentName === "expressions" && childName === 0) { assert_1.default.strictEqual(parent.expressions[0], child); continue; } if (n.CallExpression.check(parent) && childName === "callee") { assert_1.default.strictEqual(parent.callee, child); continue; } if (n.MemberExpression.check(parent) && childName === "object") { assert_1.default.strictEqual(parent.object, child); continue; } if (n.ConditionalExpression.check(parent) && childName === "test") { assert_1.default.strictEqual(parent.test, child); continue; } if (isBinary(parent) && childName === "left") { assert_1.default.strictEqual(parent.left, child); continue; } if (n.UnaryExpression.check(parent) && !parent.prefix && childName === "argument") { assert_1.default.strictEqual(parent.argument, child); continue; } return false; } return true; }; exports.default = FastPath;