A new widget block: BlocMuteSelector. Select a part of the state and create a mutable object.

[MattiaPispisa]

A new widget block: BlocMuteSelector. Based on the state of a bloc, it allows you to select a part of the state and create a mutable object.

Status

READY

Breaking Changes

NO

Description

A use case I encounter in some situations (especially when creating complex forms) is having an object that changes over time but should not reside in the bloc state. For example, I have TextFormFields that require using a TextEditingController because their content can change due to actions outside the field itself. Recreating the TextEditingController would necessitate repositioning the cursor correctly and dealing with other issues. By creating a mutable state, I can create and modify a TextEditingController. The muteOrCopy function takes the previous mutable state and the current bloc state as inputs, allowing me to apply controls based on the previous value. Since it is mutable, you cannot rely on the muteOrCopy function to execute the builder only when the state has actually changed, so muteWhen is used, which effectively works like BlocListener's listenWhen. The muteOrCopy function has a dual purpose; if it returns null, the state is expected to be mutable, but if it returns a new state, a comparison between the previous and new state is applied to update only if it has actually changed. The create function is executed on the first render, while the muteOrCopy function is applied for all subsequent renders.

Another use case where this can be helpful is when ValueNotifiers are required to satisfy third-party libraries, and I do not want to change the bloc state based on new third-party constraints.

Type of Change

• [ X] ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• [ X] 📝 Documentation
• 🗑️ Chore

[felangel]

@MattiaPispisa can you please file an issue clearly describing the problem you’re facing so we can discuss and align on a solution? Thanks!

[MattiaPispisa]

Sure, I created the issue under "Feature Request" to discuss my problem, as it seemed like the most appropriate category among the available ones.

Issue

[felangel]

Closing this for now while we discuss the solution in the issue. I'll follow up this weekend, thanks!