Cannot read property '0' of undefined

[guillemcordoba]

When calling a zome function, this error occurs:

inline-module-index-1.js:9053 Uncaught TypeError: Cannot read property '0' of undefined
    at ParentAPI.<anonymous> (inline-module-index-1.js:9053)
    at ParentAPI.listener (inline-module-index-1.js:8904)

following the trail it's because of this line:

cross-origin-message-bus/src/index.ts

Line 205 in 86c3fb9

let [k, v] = data;

, where data seems to be undefined.

This is a bit weird, because the app continues to work, and all the zome functions that we call do return something.

[timotree3]

I am guessing the exception is on this line

cross-origin-message-bus/src/index.ts

Line 338 in 86c3fb9

const fn = this.methods[method];

[timotree3]

I don't think the exception can come from the destructuring assignment you linked because in Chromium, destructuring undefined gives:

Uncaught TypeError: undefined is not iterable (cannot read property Symbol(Symbol.iterator))

and indexing undefined gives

Uncaught TypeError: Cannot read property '0' of undefined

[guillemcordoba]

Hum this is interesting... This is the actual executing minified js:

                        child.on('response', function (data) {
                            var k = data[0], v = data[1];
                            // log.info("Received response for msg_id:", k );
                            var _a = _this.responses[k], f = _a[0], r = _a[1];
                            if (v instanceof Error)
                                r(v);
                            else
                                f(v);
                            delete _this.responses[k];

And I thought that the data[0] was the problem.

[timotree3]

Gotcha. That seems to imply that .emit("response", undefined) is called on a ParentAPI somewhere, but every single instance of "response" is accompanied by an array of length 2. I don't see how this error could possibly be happening

[guillemcordoba]

Yeah I don't know... I did a console.log on data and it never showed undefined. But still this is what I'm getting... Let's see if others get the same when this becomes more used.