@typescript-eslint/eslint-plugin
Version:
TypeScript plugin for ESLint
181 lines • 8.09 kB
JavaScript
;
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
var desc = Object.getOwnPropertyDescriptor(m, k);
if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
desc = { enumerable: true, get: function() { return m[k]; } };
}
Object.defineProperty(o, k2, desc);
}) : (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
o[k2] = m[k];
}));
var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
o["default"] = v;
});
var __importStar = (this && this.__importStar) || function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
__setModuleDefault(result, mod);
return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
const tsutils = __importStar(require("ts-api-utils"));
const ts = __importStar(require("typescript"));
const util_1 = require("../util");
const shared_1 = require("./enum-utils/shared");
/**
* @returns Whether the right type is an unsafe comparison against any left type.
*/
function typeViolates(leftTypeParts, rightType) {
const leftEnumValueTypes = new Set(leftTypeParts.map(getEnumValueType));
return ((leftEnumValueTypes.has(ts.TypeFlags.Number) && isNumberLike(rightType)) ||
(leftEnumValueTypes.has(ts.TypeFlags.String) && isStringLike(rightType)));
}
function isNumberLike(type) {
const typeParts = tsutils.intersectionTypeParts(type);
return typeParts.some(typePart => {
return tsutils.isTypeFlagSet(typePart, ts.TypeFlags.Number | ts.TypeFlags.NumberLike);
});
}
function isStringLike(type) {
const typeParts = tsutils.intersectionTypeParts(type);
return typeParts.some(typePart => {
return tsutils.isTypeFlagSet(typePart, ts.TypeFlags.String | ts.TypeFlags.StringLike);
});
}
/**
* @returns What type a type's enum value is (number or string), if either.
*/
function getEnumValueType(type) {
return tsutils.isTypeFlagSet(type, ts.TypeFlags.EnumLike)
? tsutils.isTypeFlagSet(type, ts.TypeFlags.NumberLiteral)
? ts.TypeFlags.Number
: ts.TypeFlags.String
: undefined;
}
exports.default = (0, util_1.createRule)({
name: 'no-unsafe-enum-comparison',
meta: {
hasSuggestions: true,
type: 'suggestion',
docs: {
description: 'Disallow comparing an enum value with a non-enum value',
recommended: 'recommended',
requiresTypeChecking: true,
},
messages: {
mismatchedCase: 'The case statement does not have a shared enum type with the switch predicate.',
mismatchedCondition: 'The two values in this comparison do not have a shared enum type.',
replaceValueWithEnum: 'Replace with an enum value comparison.',
},
schema: [],
},
defaultOptions: [],
create(context) {
const parserServices = (0, util_1.getParserServices)(context);
const typeChecker = parserServices.program.getTypeChecker();
function isMismatchedComparison(leftType, rightType) {
// Allow comparisons that don't have anything to do with enums:
//
// ```ts
// 1 === 2;
// ```
const leftEnumTypes = (0, shared_1.getEnumTypes)(typeChecker, leftType);
const rightEnumTypes = new Set((0, shared_1.getEnumTypes)(typeChecker, rightType));
if (leftEnumTypes.length === 0 && rightEnumTypes.size === 0) {
return false;
}
// Allow comparisons that share an enum type:
//
// ```ts
// Fruit.Apple === Fruit.Banana;
// ```
for (const leftEnumType of leftEnumTypes) {
if (rightEnumTypes.has(leftEnumType)) {
return false;
}
}
// We need to split the type into the union type parts in order to find
// valid enum comparisons like:
//
// ```ts
// declare const something: Fruit | Vegetable;
// something === Fruit.Apple;
// ```
const leftTypeParts = tsutils.unionTypeParts(leftType);
const rightTypeParts = tsutils.unionTypeParts(rightType);
// If a type exists in both sides, we consider this comparison safe:
//
// ```ts
// declare const fruit: Fruit.Apple | 0;
// fruit === 0;
// ```
for (const leftTypePart of leftTypeParts) {
if (rightTypeParts.includes(leftTypePart)) {
return false;
}
}
return (typeViolates(leftTypeParts, rightType) ||
typeViolates(rightTypeParts, leftType));
}
return {
'BinaryExpression[operator=/^[<>!=]?={0,2}$/]'(node) {
const leftType = parserServices.getTypeAtLocation(node.left);
const rightType = parserServices.getTypeAtLocation(node.right);
if (isMismatchedComparison(leftType, rightType)) {
context.report({
messageId: 'mismatchedCondition',
node,
suggest: [
{
messageId: 'replaceValueWithEnum',
fix(fixer) {
// Replace the right side with an enum key if possible:
//
// ```ts
// Fruit.Apple === 'apple'; // Fruit.Apple === Fruit.Apple
// ```
const leftEnumKey = (0, shared_1.getEnumKeyForLiteral)((0, shared_1.getEnumLiterals)(leftType), (0, util_1.getStaticValue)(node.right)?.value);
if (leftEnumKey) {
return fixer.replaceText(node.right, leftEnumKey);
}
// Replace the left side with an enum key if possible:
//
// ```ts
// declare const fruit: Fruit;
// 'apple' === Fruit.Apple; // Fruit.Apple === Fruit.Apple
// ```
const rightEnumKey = (0, shared_1.getEnumKeyForLiteral)((0, shared_1.getEnumLiterals)(rightType), (0, util_1.getStaticValue)(node.left)?.value);
if (rightEnumKey) {
return fixer.replaceText(node.left, rightEnumKey);
}
return null;
},
},
],
});
}
},
SwitchCase(node) {
// Ignore `default` cases.
if (node.test == null) {
return;
}
const { parent } = node;
const leftType = parserServices.getTypeAtLocation(parent.discriminant);
const rightType = parserServices.getTypeAtLocation(node.test);
if (isMismatchedComparison(leftType, rightType)) {
context.report({
messageId: 'mismatchedCase',
node,
});
}
},
};
},
});
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