Making some progress with adding scripting capabilities to dynamo-browse. I’ve selected a pretty full-featured JS interpreter called goja. It has full support for ECMAScript 5.1 and some pretty good coverage of ES6 as well. It also has an event loop, which means that features such as setTimeout and promises come out of the box, which is nice. Best of all, it’s written in Go, meaning a single memory space and shared garbage collector.

I’ve started working the extension interface. I came up with a bit of a draft during the weekend and now just implementing the various bindings. I don’t want to go too fast here. I’m just thinking about all the cautionary tales from those that were responsible for making APIs, and introducing mistakes that they had to live with. I imagine one way to avoid this is to play with the extension API for as long as it make sense, smoothing out any rough edges when I find them.

It’s still early days, but here are some of the test scripts I’ve been writing:

// Define a new "hello" command which will ask for your name and
// print it at the bottom.
const dynamobrowse = require("audax:dynamo-browse");

dynamobrowse.session.registerCommand("hello", () => {
    dynamobrowse.ui.prompt("What is your name? ").then((name) => {
       dynamobrowse.ui.alert("Hello, " + name);

The prompt method here asks the user for a line of text, and will return the user’s input. It acts a bit like the prompt function in the browser, except that it uses promises. Unfortunately, Goja does not yet support async/await so that means that anonymous functions will need to do for the time being (at least Goja supports arrow functions).

Here’s another script, which prints out the name of the table, and set the value of the address field on the first row:

const dynamobrowse = require("audax:dynamo-browse");

dynamobrowse.session.registerCommand("bla", () => {
    let rs = dynamobrowse.session.currentResultSet;
    let tableName =;
    dynamobrowse.ui.alert("Current table name = " + tableName);
    rs.rows[0].item.address = "123 Fake St.";

The rows array, and item object, makes use of DynamicArray and DyanmicObject, which is a nice feature in Goja in which you do not need to set the elements in the array, or fields on the object explicitly. Instead, when a field or element is looked up, Goja will effectively call a method on a Go interface with the field name or element index as a parameter. This is quite handy, particularly as it cuts down on memory copies.

These scripts work but they do require some improvements. For example, some of these names could possibly be shortened, just to reduce the amount of typing involved. They also need a lot of testing: I have no idea if the updated address in the example above will be saved properly.

Even so, I’m quite happy about how quickly this is coming along. Hopefully soon I’ll be in a position to write the test script I’m planning for work.

Also, I got my first beta user. Someone at work saw me use dynamo-browse today and asked where he could get a copy. I’m just so glad I got the website finished in time.