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Edit: /home/techb158/balavpn.abdallabala.com/node_modules/eslint/lib/rules/constructor-super.js (12051B)
/**
* @fileoverview A rule to verify `super()` callings in constructor.
* @author Toru Nagashima
*/
"use strict";
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Checks whether or not a given node is a constructor.
* @param {ASTNode} node A node to check. This node type is one of
* `Program`, `FunctionDeclaration`, `FunctionExpression`, and
* `ArrowFunctionExpression`.
* @returns {boolean} `true` if the node is a constructor.
*/
function isConstructorFunction(node) {
return (
node.type === "FunctionExpression" &&
node.parent.type === "MethodDefinition" &&
node.parent.kind === "constructor"
);
}
/**
* Checks whether a given node can be a constructor or not.
* @param {ASTNode} node A node to check.
* @returns {boolean} `true` if the node can be a constructor.
*/
function isPossibleConstructor(node) {
if (!node) {
return false;
}
switch (node.type) {
case "ClassExpression":
case "FunctionExpression":
case "ThisExpression":
case "MemberExpression":
case "CallExpression":
case "NewExpression":
case "ChainExpression":
case "YieldExpression":
case "TaggedTemplateExpression":
case "MetaProperty":
return true;
case "Identifier":
return node.name !== "undefined";
case "AssignmentExpression":
if (["=", "&&="].includes(node.operator)) {
return isPossibleConstructor(node.right);
}
if (["||=", "??="].includes(node.operator)) {
return (
isPossibleConstructor(node.left) ||
isPossibleConstructor(node.right)
);
}
/**
* All other assignment operators are mathematical assignment operators (arithmetic or bitwise).
* An assignment expression with a mathematical operator can either evaluate to a primitive value,
* or throw, depending on the operands. Thus, it cannot evaluate to a constructor function.
*/
return false;
case "LogicalExpression":
/*
* If the && operator short-circuits, the left side was falsy and therefore not a constructor, and if
* it doesn't short-circuit, it takes the value from the right side, so the right side must always be a
* possible constructor. A future improvement could verify that the left side could be truthy by
* excluding falsy literals.
*/
if (node.operator === "&&") {
return isPossibleConstructor(node.right);
}
return (
isPossibleConstructor(node.left) ||
isPossibleConstructor(node.right)
);
case "ConditionalExpression":
return (
isPossibleConstructor(node.alternate) ||
isPossibleConstructor(node.consequent)
);
case "SequenceExpression": {
const lastExpression = node.expressions.at(-1);
return isPossibleConstructor(lastExpression);
}
default:
return false;
}
}
/**
* A class to store information about a code path segment.
*/
class SegmentInfo {
/**
* Indicates if super() is called in all code paths.
* @type {boolean}
*/
calledInEveryPaths = false;
/**
* Indicates if super() is called in any code paths.
* @type {boolean}
*/
calledInSomePaths = false;
/**
* The nodes which have been validated and don't need to be reconsidered.
* @type {ASTNode[]}
*/
validNodes = [];
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../types').Rule.RuleModule} */
module.exports = {
meta: {
type: "problem",
docs: {
description: "Require `super()` calls in constructors",
recommended: true,
url: "https://eslint.org/docs/latest/rules/constructor-super",
},
schema: [],
messages: {
missingSome: "Lacked a call of 'super()' in some code paths.",
missingAll: "Expected to call 'super()'.",
duplicate: "Unexpected duplicate 'super()'.",
badSuper:
"Unexpected 'super()' because 'super' is not a constructor.",
},
},
create(context) {
/*
* {{hasExtends: boolean, scope: Scope, codePath: CodePath}[]}
* Information for each constructor.
* - upper: Information of the upper constructor.
* - hasExtends: A flag which shows whether own class has a valid `extends`
* part.
* - scope: The scope of own class.
* - codePath: The code path object of the constructor.
*/
let funcInfo = null;
/**
* @type {Record
}
*/
const segInfoMap = Object.create(null);
/**
* Gets the flag which shows `super()` is called in some paths.
* @param {CodePathSegment} segment A code path segment to get.
* @returns {boolean} The flag which shows `super()` is called in some paths
*/
function isCalledInSomePath(segment) {
return (
segment.reachable && segInfoMap[segment.id].calledInSomePaths
);
}
/**
* Determines if a segment has been seen in the traversal.
* @param {CodePathSegment} segment A code path segment to check.
* @returns {boolean} `true` if the segment has been seen.
*/
function hasSegmentBeenSeen(segment) {
return !!segInfoMap[segment.id];
}
/**
* Gets the flag which shows `super()` is called in all paths.
* @param {CodePathSegment} segment A code path segment to get.
* @returns {boolean} The flag which shows `super()` is called in all paths.
*/
function isCalledInEveryPath(segment) {
return (
segment.reachable && segInfoMap[segment.id].calledInEveryPaths
);
}
return {
/**
* Stacks a constructor information.
* @param {CodePath} codePath A code path which was started.
* @param {ASTNode} node The current node.
* @returns {void}
*/
onCodePathStart(codePath, node) {
if (isConstructorFunction(node)) {
// Class > ClassBody > MethodDefinition > FunctionExpression
const classNode = node.parent.parent.parent;
const superClass = classNode.superClass;
funcInfo = {
upper: funcInfo,
isConstructor: true,
hasExtends: Boolean(superClass),
superIsConstructor: isPossibleConstructor(superClass),
codePath,
currentSegments: new Set(),
};
} else {
funcInfo = {
upper: funcInfo,
isConstructor: false,
hasExtends: false,
superIsConstructor: false,
codePath,
currentSegments: new Set(),
};
}
},
/**
* Pops a constructor information.
* And reports if `super()` lacked.
* @param {CodePath} codePath A code path which was ended.
* @param {ASTNode} node The current node.
* @returns {void}
*/
onCodePathEnd(codePath, node) {
const hasExtends = funcInfo.hasExtends;
// Pop.
funcInfo = funcInfo.upper;
if (!hasExtends) {
return;
}
// Reports if `super()` lacked.
const returnedSegments = codePath.returnedSegments;
const calledInEveryPaths =
returnedSegments.every(isCalledInEveryPath);
const calledInSomePaths =
returnedSegments.some(isCalledInSomePath);
if (!calledInEveryPaths) {
context.report({
messageId: calledInSomePaths
? "missingSome"
: "missingAll",
node: node.parent,
});
}
},
/**
* Initialize information of a given code path segment.
* @param {CodePathSegment} segment A code path segment to initialize.
* @param {CodePathSegment} node Node that starts the segment.
* @returns {void}
*/
onCodePathSegmentStart(segment, node) {
funcInfo.currentSegments.add(segment);
if (!(funcInfo.isConstructor && funcInfo.hasExtends)) {
return;
}
// Initialize info.
const info = (segInfoMap[segment.id] = new SegmentInfo());
const seenPrevSegments =
segment.prevSegments.filter(hasSegmentBeenSeen);
// When there are previous segments, aggregates these.
if (seenPrevSegments.length > 0) {
info.calledInSomePaths =
seenPrevSegments.some(isCalledInSomePath);
info.calledInEveryPaths =
seenPrevSegments.every(isCalledInEveryPath);
}
/*
* ForStatement > *.update segments are a special case as they are created in advance,
* without seen previous segments. Since they logically don't affect `calledInEveryPaths`
* calculations, and they can never be a lone previous segment of another one, we'll set
* their `calledInEveryPaths` to `true` to effectively ignore them in those calculations.
* .
*/
if (
node.parent &&
node.parent.type === "ForStatement" &&
node.parent.update === node
) {
info.calledInEveryPaths = true;
}
},
onUnreachableCodePathSegmentStart(segment) {
funcInfo.currentSegments.add(segment);
},
onUnreachableCodePathSegmentEnd(segment) {
funcInfo.currentSegments.delete(segment);
},
onCodePathSegmentEnd(segment) {
funcInfo.currentSegments.delete(segment);
},
/**
* Update information of the code path segment when a code path was
* looped.
* @param {CodePathSegment} fromSegment The code path segment of the
* end of a loop.
* @param {CodePathSegment} toSegment A code path segment of the head
* of a loop.
* @returns {void}
*/
onCodePathSegmentLoop(fromSegment, toSegment) {
if (!(funcInfo.isConstructor && funcInfo.hasExtends)) {
return;
}
funcInfo.codePath.traverseSegments(
{ first: toSegment, last: fromSegment },
(segment, controller) => {
const info = segInfoMap[segment.id];
// skip segments after the loop
if (!info) {
controller.skip();
return;
}
const seenPrevSegments =
segment.prevSegments.filter(hasSegmentBeenSeen);
const calledInSomePreviousPaths =
seenPrevSegments.some(isCalledInSomePath);
const calledInEveryPreviousPaths =
seenPrevSegments.every(isCalledInEveryPath);
info.calledInSomePaths ||= calledInSomePreviousPaths;
info.calledInEveryPaths ||= calledInEveryPreviousPaths;
// If flags become true anew, reports the valid nodes.
if (calledInSomePreviousPaths) {
const nodes = info.validNodes;
info.validNodes = [];
for (let i = 0; i < nodes.length; ++i) {
const node = nodes[i];
context.report({
messageId: "duplicate",
node,
});
}
}
},
);
},
/**
* Checks for a call of `super()`.
* @param {ASTNode} node A CallExpression node to check.
* @returns {void}
*/
"CallExpression:exit"(node) {
if (!(funcInfo.isConstructor && funcInfo.hasExtends)) {
return;
}
// Skips except `super()`.
if (node.callee.type !== "Super") {
return;
}
// Reports if needed.
const segments = funcInfo.currentSegments;
let duplicate = false;
let info = null;
for (const segment of segments) {
if (segment.reachable) {
info = segInfoMap[segment.id];
duplicate = duplicate || info.calledInSomePaths;
info.calledInSomePaths = info.calledInEveryPaths = true;
}
}
if (info) {
if (duplicate) {
context.report({
messageId: "duplicate",
node,
});
} else if (!funcInfo.superIsConstructor) {
context.report({
messageId: "badSuper",
node,
});
} else {
info.validNodes.push(node);
}
}
},
/**
* Set the mark to the returned path as `super()` was called.
* @param {ASTNode} node A ReturnStatement node to check.
* @returns {void}
*/
ReturnStatement(node) {
if (!(funcInfo.isConstructor && funcInfo.hasExtends)) {
return;
}
// Skips if no argument.
if (!node.argument) {
return;
}
// Returning argument is a substitute of 'super()'.
const segments = funcInfo.currentSegments;
for (const segment of segments) {
if (segment.reachable) {
const info = segInfoMap[segment.id];
info.calledInSomePaths = info.calledInEveryPaths = true;
}
}
},
};
},
};