eslint-plugin-complete/dist/rules/no-let-any.js

An ESLint plugin that contains useful rules.

import { ESLintUtils } from "@typescript-eslint/utils";
import { isAny } from "../typeUtils.js";
import { createRule } from "../utils.js";
export const noLetAny = createRule({
    name: "no-let-any",
    meta: {
        type: "problem",
        docs: {
            description: "Disallows declaring variables with let that do not have a type",
            recommended: true,
            requiresTypeChecking: true,
        },
        schema: [],
        messages: {
            noType: "Variables must be declared with a type.",
        },
    },
    defaultOptions: [],
    create(context) {
        const parserServices = ESLintUtils.getParserServices(context);
        const checker = parserServices.program.getTypeChecker();
        return {
            VariableDeclaration(node) {
                if (node.kind !== "let") {
                    return;
                }
                for (const declaration of node.declarations) {
                    const tsNode = parserServices.esTreeNodeToTSNodeMap.get(declaration);
                    /**
                     * We have to use `leftTSNode.name` instead of `leftTSNode` to avoid run-time errors
                     * because the `typeChecker.getTypeAtLocation` method expects a `ts.BindingName` instead
                     * of a `ts.VariableDeclaration`: https://github.com/microsoft/TypeScript/issues/48878
                     */
                    const type = checker.getTypeAtLocation(tsNode.name);
                    if (isAny(type)) {
                        context.report({
                            node,
                            messageId: "noType",
                        });
                    }
                }
            },
        };
    },
});