Cannot read property 'id' of null

[matthiasbruns]

Files that I talk about:

• src/reducers/list/delete/success.ts
• dist/reducers/map/delete/success.js

I've found something really weird. I know how to fix it, but would like to know, if this behaviour desired.
My default state is this:

const emptyState = {
  _meta: {
    isFetching: true,
    isSubmitting: false
  },
  _error: null
};

As you can see, there is a field _error, which is null by default and will be reset to null during the reduction, if no error happens.

When I want to delete an item, this happens:

Stacktrace:

TypeError: Cannot read property 'id' of null
    at predicate (app.js:99228)
    at app.js:35899
    at XWrap.f (app.js:28303)
    at XWrap.module.exports.XWrap.@@transducer/step (app.js:36172)
    at _arrayReduce (app.js:15717)
    at _reduce (app.js:15750)
    at app.js:28302
    at app.js:14662
    at f2 (app.js:936)
    at reject (app.js:24663)

It took me a bit to find out that calling deleteSuccess causes this error.
The reason is, that predicate(existingRecord) receives a null value, because _error is null.
This causes this error: null['id']

function success(config, current, record) {
    invariants_1.default(invariantArgs, config, current, record);
    var key = config.key;
    var deleteId = record[key];
    function predicate(existingRecord) {
        return deleteId == existingRecord[key];
    }
    return r.reject(predicate, current);
}

I would suggest, that you add a null check to the deleteId check - something like this:

function predicate(existingRecord) {
    return existingRecord && deleteId == existingRecord[key];
}