node-redis/examples/subqueries.js

// Sending commands in response to other commands.
// This example runs "type" against every key in the database
//
var client = require("redis").createClient();

client.keys("*", function (err, keys) {
    keys.forEach(function (key, pos) {
        client.type(key, function (err, keytype) {
            console.log(key + " is " + keytype);
            if (pos === (keys.length - 1)) {
                client.quit();
            }
        });
    });
});