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- "use strict";
- const astUtils = require("./utils/ast-utils");
- function isConstructorFunction(node) {
- return (
- node.type === "FunctionExpression" &&
- node.parent.type === "MethodDefinition" &&
- node.parent.kind === "constructor"
- );
- }
- module.exports = {
- meta: {
- type: "problem",
- docs: {
- description: "Disallow `this`/`super` before calling `super()` in constructors",
- recommended: true,
- url: "https://eslint.org/docs/latest/rules/no-this-before-super"
- },
- schema: [],
- messages: {
- noBeforeSuper: "'{{kind}}' is not allowed before 'super()'."
- }
- },
- create(context) {
-
- let funcInfo = null;
-
- let segInfoMap = Object.create(null);
-
- function isCalled(segment) {
- return !segment.reachable || segInfoMap[segment.id].superCalled;
- }
-
- function isInConstructorOfDerivedClass() {
- return Boolean(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends);
- }
-
- function isEverySegmentCalled(segments) {
- for (const segment of segments) {
- if (!isCalled(segment)) {
- return false;
- }
- }
- return true;
- }
-
- function isBeforeCallOfSuper() {
- return (
- isInConstructorOfDerivedClass() &&
- !isEverySegmentCalled(funcInfo.currentSegments)
- );
- }
-
- function setInvalid(node) {
- const segments = funcInfo.currentSegments;
- for (const segment of segments) {
- if (segment.reachable) {
- segInfoMap[segment.id].invalidNodes.push(node);
- }
- }
- }
-
- function setSuperCalled() {
- const segments = funcInfo.currentSegments;
- for (const segment of segments) {
- if (segment.reachable) {
- segInfoMap[segment.id].superCalled = true;
- }
- }
- }
- return {
-
- onCodePathStart(codePath, node) {
- if (isConstructorFunction(node)) {
-
- const classNode = node.parent.parent.parent;
- funcInfo = {
- upper: funcInfo,
- isConstructor: true,
- hasExtends: Boolean(
- classNode.superClass &&
- !astUtils.isNullOrUndefined(classNode.superClass)
- ),
- codePath,
- currentSegments: new Set()
- };
- } else {
- funcInfo = {
- upper: funcInfo,
- isConstructor: false,
- hasExtends: false,
- codePath,
- currentSegments: new Set()
- };
- }
- },
-
- onCodePathEnd(codePath) {
- const isDerivedClass = funcInfo.hasExtends;
- funcInfo = funcInfo.upper;
- if (!isDerivedClass) {
- return;
- }
- codePath.traverseSegments((segment, controller) => {
- const info = segInfoMap[segment.id];
- for (let i = 0; i < info.invalidNodes.length; ++i) {
- const invalidNode = info.invalidNodes[i];
- context.report({
- messageId: "noBeforeSuper",
- node: invalidNode,
- data: {
- kind: invalidNode.type === "Super" ? "super" : "this"
- }
- });
- }
- if (info.superCalled) {
- controller.skip();
- }
- });
- },
-
- onCodePathSegmentStart(segment) {
- funcInfo.currentSegments.add(segment);
- if (!isInConstructorOfDerivedClass()) {
- return;
- }
-
- segInfoMap[segment.id] = {
- superCalled: (
- segment.prevSegments.length > 0 &&
- segment.prevSegments.every(isCalled)
- ),
- invalidNodes: []
- };
- },
- onUnreachableCodePathSegmentStart(segment) {
- funcInfo.currentSegments.add(segment);
- },
- onUnreachableCodePathSegmentEnd(segment) {
- funcInfo.currentSegments.delete(segment);
- },
- onCodePathSegmentEnd(segment) {
- funcInfo.currentSegments.delete(segment);
- },
-
- onCodePathSegmentLoop(fromSegment, toSegment) {
- if (!isInConstructorOfDerivedClass()) {
- return;
- }
-
- funcInfo.codePath.traverseSegments(
- { first: toSegment, last: fromSegment },
- (segment, controller) => {
- const info = segInfoMap[segment.id];
- if (info.superCalled) {
- info.invalidNodes = [];
- controller.skip();
- } else if (
- segment.prevSegments.length > 0 &&
- segment.prevSegments.every(isCalled)
- ) {
- info.superCalled = true;
- info.invalidNodes = [];
- }
- }
- );
- },
-
- ThisExpression(node) {
- if (isBeforeCallOfSuper()) {
- setInvalid(node);
- }
- },
-
- Super(node) {
- if (!astUtils.isCallee(node) && isBeforeCallOfSuper()) {
- setInvalid(node);
- }
- },
-
- "CallExpression:exit"(node) {
- if (node.callee.type === "Super" && isBeforeCallOfSuper()) {
- setSuperCalled();
- }
- },
-
- "Program:exit"() {
- segInfoMap = Object.create(null);
- }
- };
- }
- };
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