catch exceptions and show them somewhere

[ajafff]

https://agentcooper.github.io/typescript-play/#code/JYMwBAFAQg9jA2BTAhgOwgSgwKDHsALgJ4AOiYAKmALxhpFA

Throws an exception, because TypeScript currently doesn't handle this correctly. That's already tracked in the TypeScript repo.

Uncaught Error: Cannot read property 'kind' of undefined

TypeError: Cannot read property 'kind' of undefined
    at Object.e.isBlock (typescriptServices.js:7)
    at _t (typescriptServices.js:7)
    at typescriptServices.js:7
    at V (typescriptServices.js:7)
    at emitNodeWithSourceMap (typescriptServices.js:7)
    at q (typescriptServices.js:7)
    at b (typescriptServices.js:7)
    at emitNodeWithComments (typescriptServices.js:7)
    at U (typescriptServices.js:7)
    at emitNodeWithNotification (typescriptServices.js:7)
    at Object.e.isBlock (typescriptServices.js:7)
    at _t (typescriptServices.js:7)
    at typescriptServices.js:7
    at V (typescriptServices.js:7)
    at emitNodeWithSourceMap (typescriptServices.js:7)
    at q (typescriptServices.js:7)
    at b (typescriptServices.js:7)
    at emitNodeWithComments (typescriptServices.js:7)
    at U (typescriptServices.js:7)
    at emitNodeWithNotification (typescriptServices.js:7)
    at errors.ts:81

As a regular user I don't notice this exception without opening devtools. I only see that transpiling stops at a certain point.
It would be nice to get this exception displayed somewhere on the website.

[agentcooper]

Do you want a full exception message or just an indicator that it happened and you might need to check the console?

[ajafff]

An indicator would work for me. But you could actually use the space where the transpiled output is shown to display the full stack trace since there will be no transpilation in case of an exception.