node/tools/eslint/lib/rules/guard-for-in.js

/**
 * @fileoverview Rule to flag for-in loops without if statements inside
 * @author Nicholas C. Zakas
 */

"use strict";

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

module.exports = function(context) {

    return {

        "ForInStatement": function(node) {

            /*
             * If the for-in statement has {}, then the real body is the body
             * of the BlockStatement. Otherwise, just use body as provided.
             */
            var body = node.body.type === "BlockStatement" ? node.body.body[0] : node.body;

            if (body && body.type !== "IfStatement") {
                context.report(node, "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype.");
            }
        }
    };

};

module.exports.schema = [];