node_modules/@typescript-eslint/eslint-plugin/dist/rules/no-base-to-string.js

"use strict";
var __importStar = (this && this.__importStar) || function (mod) {
    if (mod && mod.__esModule) return mod;
    var result = {};
    if (mod != null) for (var k in mod) if (Object.hasOwnProperty.call(mod, k)) result[k] = mod[k];
    result["default"] = mod;
    return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
const experimental_utils_1 = require("@typescript-eslint/experimental-utils");
const ts = __importStar(require("typescript"));
const util = __importStar(require("../util"));
var Usefulness;
(function (Usefulness) {
    Usefulness[Usefulness["Always"] = 0] = "Always";
    Usefulness["Never"] = "will";
    Usefulness["Sometimes"] = "may";
})(Usefulness || (Usefulness = {}));
exports.default = util.createRule({
    name: 'no-base-to-string',
    meta: {
        docs: {
            description: 'Requires that `.toString()` is only called on objects which provide useful information when stringified',
            category: 'Best Practices',
            recommended: false,
            requiresTypeChecking: true,
        },
        messages: {
            baseToString: "'{{name}} {{certainty}} evaluate to '[Object object]' when stringified.",
        },
        schema: [],
        type: 'suggestion',
    },
    defaultOptions: [],
    create(context) {
        const parserServices = util.getParserServices(context);
        const typeChecker = parserServices.program.getTypeChecker();
        function checkExpression(node, type) {
            if (node.type === experimental_utils_1.AST_NODE_TYPES.Literal) {
                return;
            }
            const certainty = collectToStringCertainty((type !== null && type !== void 0 ? type : typeChecker.getTypeAtLocation(parserServices.esTreeNodeToTSNodeMap.get(node))));
            if (certainty === Usefulness.Always) {
                return;
            }
            context.report({
                data: {
                    certainty,
                    name: context.getSourceCode().getText(node),
                },
                messageId: 'baseToString',
                node,
            });
        }
        function collectToStringCertainty(type) {
            const toString = typeChecker.getPropertyOfType(type, 'toString');
            if (toString === undefined || toString.declarations.length === 0) {
                return Usefulness.Always;
            }
            if (toString.declarations.every(({ parent }) => !ts.isInterfaceDeclaration(parent) || parent.name.text !== 'Object')) {
                return Usefulness.Always;
            }
            if (!type.isUnion()) {
                return Usefulness.Never;
            }
            for (const subType of type.types) {
                if (collectToStringCertainty(subType) !== Usefulness.Never) {
                    return Usefulness.Sometimes;
                }
            }
            return Usefulness.Never;
        }
        return {
            'AssignmentExpression[operator = "+="], BinaryExpression[operator = "+"]'(node) {
                const leftType = typeChecker.getTypeAtLocation(parserServices.esTreeNodeToTSNodeMap.get(node.left));
                const rightType = typeChecker.getTypeAtLocation(parserServices.esTreeNodeToTSNodeMap.get(node.right));
                if (util.getTypeName(typeChecker, leftType) === 'string') {
                    checkExpression(node.right, rightType);
                }
                else if (util.getTypeName(typeChecker, rightType) === 'string') {
                    checkExpression(node.left, leftType);
                }
            },
            'CallExpression > MemberExpression.callee > Identifier[name = "toString"].property'(node) {
                const memberExpr = node.parent;
                checkExpression(memberExpr.object);
            },
            TemplateLiteral(node) {
                for (const expression of node.expressions) {
                    checkExpression(expression);
                }
            },
        };
    },
});
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