JavaScript Ergonomics

Currently, there are two issues with the JavaScript / TypeScript bindings that make development inconvenient for IC developers.

1. Options

• Optional nested values in JavaScript are denoted idiomatically using the Optional Chaining operator (?.)
• Our generated pattern, of a null value being represented as [] does not align with expectations of developers, as Arrays are used to represent ordered data.

2. Variants

• For Variants such as Result.Result, we get back a typing that is not ideal for JavaScript, and requires developers to add a significant amount of boilerplate and error handling.
• a type of { ok : () } | { err: string } cannot be safely accessed as result.ok or result.err, but requires the user to write something like

if ('ok' in result){
 // continue
}
else if ('err' in result) {
 // handle result.err
}

* This code is unsafe, and is problematic for TypeScript in particular. Instanceof is also not reliable for determining which case is represented.

Describe the solution you'd like

• Replace options with Optional Chaining
  • may require additional support in the JS Agent for converting null back to the candid type
• Handle variants with a "kind" attribute that will always be present and checkable in variants