Non-deterministic software breaks the contract.

Anything that isn't explicitly enforced by contract is vulnerable to misunderstandings. It's doing your teammates a great service, and reducing everyone's effort, by eliminating ambiguity and enforcing information flow by design.

In 1994, The Unix-Haters Handbook was published containing a long list of missives about the software—everything from overly-cryptic command names that were optimized for Teletype machines, to irreversible file deletion, to unintuitive programs with far too many options. Over twenty years later, an overwhelming majority of these complaints are still valid even across the dozens of modern derivatives. Unix had become so widely used that changing its behavior would have challenging implications. For better

The $ contract for auto-sub­scrib­ing is lovely in its sim­plic­ity and flex­i­bil­ity. You can adapt your own preferred state-man­age­ment pattern or library, with or without Svelte stores as helpers. Svelte does not fuss about how you want to manage your state.

The central idea of DbC is a metaphor on how elements of a software system collaborate with each other on the basis of mutual obligations and benefits.