Make start mandatory in the Readable store api.

[fredguth]

Describe the problem

There seems to be no reason to create a Readable store which does not change. Still, not only the Readable Store api allows it, but there is a test for it, demonstrating this is intentional (

svelte/test/store/index.ts

Line 144 in 5a3a1e4

it('creates a readable store without updater', () => {

)

This seems a meaningless change, but it may help people seeing stores for the first time.

Describe the proposed solution

I would like to make start mandatory for creating a readable store.

Alternatives considered

Explain why it should be optional.

Importance

nice to have

[Conduitry]

Making this mandatory would be a breaking change.

As for why you might want a store that does not change - if you have some component/API that expects one of its props to be passed as a store, but you, the creator of the component or caller of the API, know that that value is never going to need to change, you can pass this constant store to the component/API.

[karimfromjordan]

For more context:
Related issue
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