eslint-instanceof-hazard.js

module.exports = function(context) {

    'use strict';

    return {
        BinaryExpression: function(node) {
            if (node.operator === 'instanceof' && node.left.type === 'UnaryExpression' && node.left.operator === '!') {
                context.report(node, "Check dangerous instanceof use (! has higher precedence than instanceof)");
            }
        }
    };

};