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- "use strict";
- Object.defineProperty(exports, "__esModule", { value: true });
- var tslib_1 = require("tslib");
- var assert_1 = tslib_1.__importDefault(require("assert"));
- var types = tslib_1.__importStar(require("ast-types"));
- var util = tslib_1.__importStar(require("./util"));
- var n = types.namedTypes;
- var isArray = types.builtInTypes.array;
- var isNumber = types.builtInTypes.number;
- var PRECEDENCE = {};
- [
- ["??"],
- ["||"],
- ["&&"],
- ["|"],
- ["^"],
- ["&"],
- ["==", "===", "!=", "!=="],
- ["<", ">", "<=", ">=", "in", "instanceof"],
- [">>", "<<", ">>>"],
- ["+", "-"],
- ["*", "/", "%"],
- ["**"],
- ].forEach(function (tier, i) {
- tier.forEach(function (op) {
- PRECEDENCE[op] = i;
- });
- });
- 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 = void 0; (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();
- 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 && parent.type === "ParenthesizedExpression") {
- return false;
- }
- if (node.extra && node.extra.parenthesized) {
- return true;
- }
- if (!parent)
- return false;
- // Wrap e.g. `-1` in parentheses inside `(-1) ** 2`.
- if (node.type === "UnaryExpression" &&
- parent.type === "BinaryExpression" &&
- name === "left" &&
- parent.left === node &&
- parent.operator === "**") {
- return true;
- }
- 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;
- }
- break;
- }
- default:
- return false;
- }
- break;
- 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 "OptionalIndexedAccessType":
- return node.optional && parent.type === "IndexedAccessType";
- 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 "YieldExpression":
- case "AwaitExpression":
- 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" &&
- parent.callee === node) {
- return true;
- }
- if (n.MemberExpression.check(parent) &&
- name === "object" &&
- parent.object === node) {
- return true;
- }
- if (n.TSAsExpression &&
- n.TSAsExpression.check(parent) &&
- name === "expression" &&
- parent.expression === node) {
- return true;
- }
- return isBinary(parent);
- case "ObjectExpression":
- if (parent.type === "ArrowFunctionExpression" &&
- name === "body" &&
- parent.body === node) {
- return true;
- }
- break;
- case "TSAsExpression":
- if (parent.type === "ArrowFunctionExpression" &&
- name === "body" &&
- parent.body === node &&
- 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)));
- }
- 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;
- }
- // s[i + 1] and s[i + 2] represent the array between the parent
- // SequenceExpression node and its child nodes
- if (n.SequenceExpression.check(parent) &&
- s[i + 1] === "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;
|