302 lines
10 KiB
JavaScript
302 lines
10 KiB
JavaScript
|
/**
|
||
|
|
* @fileoverview A rule to disallow using `this`/`super` before `super()`.
|
||
|
|
* @author Toru Nagashima
|
||
|
|
*/
|
||
|
|
|
||
|
|
"use strict";
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
// Requirements
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
const astUtils = require("../util/ast-utils");
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
// 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"
|
||
|
|
);
|
||
|
|
}
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
// Rule Definition
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
module.exports = {
|
||
|
|
meta: {
|
||
|
|
type: "problem",
|
||
|
|
|
||
|
|
docs: {
|
||
|
|
description: "disallow `this`/`super` before calling `super()` in constructors",
|
||
|
|
category: "ECMAScript 6",
|
||
|
|
recommended: true,
|
||
|
|
url: "https://eslint.org/docs/rules/no-this-before-super"
|
||
|
|
},
|
||
|
|
|
||
|
|
schema: []
|
||
|
|
},
|
||
|
|
|
||
|
|
create(context) {
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Information for each constructor.
|
||
|
|
* - upper: Information of the upper constructor.
|
||
|
|
* - hasExtends: A flag which shows whether the owner class has a valid
|
||
|
|
* `extends` part.
|
||
|
|
* - scope: The scope of the owner class.
|
||
|
|
* - codePath: The code path of this constructor.
|
||
|
|
*/
|
||
|
|
let funcInfo = null;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Information for each code path segment.
|
||
|
|
* Each key is the id of a code path segment.
|
||
|
|
* Each value is an object:
|
||
|
|
* - superCalled: The flag which shows `super()` called in all code paths.
|
||
|
|
* - invalidNodes: The array of invalid ThisExpression and Super nodes.
|
||
|
|
*/
|
||
|
|
let segInfoMap = Object.create(null);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Gets whether or not `super()` is called in a given code path segment.
|
||
|
|
* @param {CodePathSegment} segment - A code path segment to get.
|
||
|
|
* @returns {boolean} `true` if `super()` is called.
|
||
|
|
*/
|
||
|
|
function isCalled(segment) {
|
||
|
|
return !segment.reachable || segInfoMap[segment.id].superCalled;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Checks whether or not this is in a constructor.
|
||
|
|
* @returns {boolean} `true` if this is in a constructor.
|
||
|
|
*/
|
||
|
|
function isInConstructorOfDerivedClass() {
|
||
|
|
return Boolean(funcInfo && funcInfo.isConstructor && funcInfo.hasExtends);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Checks whether or not this is before `super()` is called.
|
||
|
|
* @returns {boolean} `true` if this is before `super()` is called.
|
||
|
|
*/
|
||
|
|
function isBeforeCallOfSuper() {
|
||
|
|
return (
|
||
|
|
isInConstructorOfDerivedClass() &&
|
||
|
|
!funcInfo.codePath.currentSegments.every(isCalled)
|
||
|
|
);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Sets a given node as invalid.
|
||
|
|
* @param {ASTNode} node - A node to set as invalid. This is one of
|
||
|
|
* a ThisExpression and a Super.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
function setInvalid(node) {
|
||
|
|
const segments = funcInfo.codePath.currentSegments;
|
||
|
|
|
||
|
|
for (let i = 0; i < segments.length; ++i) {
|
||
|
|
const segment = segments[i];
|
||
|
|
|
||
|
|
if (segment.reachable) {
|
||
|
|
segInfoMap[segment.id].invalidNodes.push(node);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Sets the current segment as `super` was called.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
function setSuperCalled() {
|
||
|
|
const segments = funcInfo.codePath.currentSegments;
|
||
|
|
|
||
|
|
for (let i = 0; i < segments.length; ++i) {
|
||
|
|
const segment = segments[i];
|
||
|
|
|
||
|
|
if (segment.reachable) {
|
||
|
|
segInfoMap[segment.id].superCalled = true;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return {
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Adds information of a constructor into the stack.
|
||
|
|
* @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;
|
||
|
|
|
||
|
|
funcInfo = {
|
||
|
|
upper: funcInfo,
|
||
|
|
isConstructor: true,
|
||
|
|
hasExtends: Boolean(
|
||
|
|
classNode.superClass &&
|
||
|
|
!astUtils.isNullOrUndefined(classNode.superClass)
|
||
|
|
),
|
||
|
|
codePath
|
||
|
|
};
|
||
|
|
} else {
|
||
|
|
funcInfo = {
|
||
|
|
upper: funcInfo,
|
||
|
|
isConstructor: false,
|
||
|
|
hasExtends: false,
|
||
|
|
codePath
|
||
|
|
};
|
||
|
|
}
|
||
|
|
},
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Removes the top of stack item.
|
||
|
|
*
|
||
|
|
* And this treverses all segments of this code path then reports every
|
||
|
|
* invalid node.
|
||
|
|
*
|
||
|
|
* @param {CodePath} codePath - A code path which was ended.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
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({
|
||
|
|
message: "'{{kind}}' is not allowed before 'super()'.",
|
||
|
|
node: invalidNode,
|
||
|
|
data: {
|
||
|
|
kind: invalidNode.type === "Super" ? "super" : "this"
|
||
|
|
}
|
||
|
|
});
|
||
|
|
}
|
||
|
|
|
||
|
|
if (info.superCalled) {
|
||
|
|
controller.skip();
|
||
|
|
}
|
||
|
|
});
|
||
|
|
},
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Initialize information of a given code path segment.
|
||
|
|
* @param {CodePathSegment} segment - A code path segment to initialize.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
onCodePathSegmentStart(segment) {
|
||
|
|
if (!isInConstructorOfDerivedClass()) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Initialize info.
|
||
|
|
segInfoMap[segment.id] = {
|
||
|
|
superCalled: (
|
||
|
|
segment.prevSegments.length > 0 &&
|
||
|
|
segment.prevSegments.every(isCalled)
|
||
|
|
),
|
||
|
|
invalidNodes: []
|
||
|
|
};
|
||
|
|
},
|
||
|
|
|
||
|
|
/**
|
||
|
|
* 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 (!isInConstructorOfDerivedClass()) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Update information inside of the loop.
|
||
|
|
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 = [];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
);
|
||
|
|
},
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Reports if this is before `super()`.
|
||
|
|
* @param {ASTNode} node - A target node.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
ThisExpression(node) {
|
||
|
|
if (isBeforeCallOfSuper()) {
|
||
|
|
setInvalid(node);
|
||
|
|
}
|
||
|
|
},
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Reports if this is before `super()`.
|
||
|
|
* @param {ASTNode} node - A target node.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
Super(node) {
|
||
|
|
if (!astUtils.isCallee(node) && isBeforeCallOfSuper()) {
|
||
|
|
setInvalid(node);
|
||
|
|
}
|
||
|
|
},
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Marks `super()` called.
|
||
|
|
* @param {ASTNode} node - A target node.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
"CallExpression:exit"(node) {
|
||
|
|
if (node.callee.type === "Super" && isBeforeCallOfSuper()) {
|
||
|
|
setSuperCalled();
|
||
|
|
}
|
||
|
|
},
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Resets state.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
"Program:exit"() {
|
||
|
|
segInfoMap = Object.create(null);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
}
|
||
|
|
};
|