Expose RadioGroupContext via useRadioGroup Hook

[NMinhNguyen]

• I have searched the issues of this repository and believe that this is not a duplicate.

Summary 💡

Expose RadioGroupContext via useRadioGroup Hook (cf. useFormControl).

Examples 🌈

https://codesandbox.io/s/material-demo-9w4yc

Motivation 🔦

I'd like the ability to easily work out whether a wrapped Radio is checked, so I can apply custom styling to a checked label, for example (see demo above). In MUI v3, this was possible because RadioGroup would use cloneElement and pass checked prop to children. With the new context implementation (#15069), I now need to hook into the context but because it's not part of public API, I'd need to use a Babel transform to import the correct module (CJS vs ESM) in my library output:

• @material-ui/core/RadioGroup/RadioGroupContext
• @material-ui/core/esm/RadioGroup/RadioGroupContext

@oliviertassinari has pointed out that we're currently exposing FormControlContext via a custom useFormControl Hook, so we could probably do the same in this instance? I'm happy to raise a PR for this.

Prior art: #11865

[eps1lon]

That looks fine to me. I can't remember a situation where exposing the context as read-only has locked us into a "bad" API.

While this specific customization is doable without using RadioGroupContext I think we can allow this.

[NMinhNguyen]

While this specific customization is doable without using RadioGroupContext I think we can allow this.

Oh, how would you do it instead?

[NMinhNguyen]

exposing the context as read-only

Do you mean excluding values such as update functions from what's returned by useRadioGroup?

[eps1lon]

While this specific customization is doable without using RadioGroupContext I think we can allow this.

Oh, how would you do it instead?

Manually do the checked test and pass it to MyFormControlLabel: https://codesandbox.io/s/material-demo-6dbb3. It's not pretty but does the job. Likely based on personal experience whether you prefer maintaining repetition or internals of third party libraries.

[maciej-gurban]

Is there a way to hook into the RadioGroupContext or any other way to get the currently selected value from RadioGroup's value? I'm also after creating a wrapper around Radio, and not using FormControlLabel.

By importing the RadioGroupContext, and trying to use it I'm getting undefined as in the consumer. I could go with creating a custom FormControlLabel, but I don't really want nor need to create a generic one which would work for other form elements - I'm only after creating custom Radios. Or would it be better for my custom Radio to already contain FormControlLabel?

[oliviertassinari]

I'm reopening as I believe we miss:

• A section in the documentation.
• To export useRadioGroup in the barrel index (js and ts).

[NMinhNguyen]

• To export useRadioGroup in the barrel index (js and ts).

FYI it already is exported via https://github.com/mui-org/material-ui/blob/5aad5f2f729066534bd9d408cc8518b51a9f0f14/packages/material-ui/src/RadioGroup/index.js#L2 and https://github.com/mui-org/material-ui/blob/5aad5f2f729066534bd9d408cc8518b51a9f0f14/packages/material-ui/src/index.js#L239

so we just need a documentation change.

[joonarahko]

I am seeing a weird situation. When I am importing the RadioGroup and useRadioGroup like this

import RadioGroup from '@material-ui/core/RadioGroup';
import useRadioGroup from '@material-ui/core/RadioGroup/useRadioGroup';

I notice that the context is being created twice. This is because @material-ui/core/RadioGroup points to the module in the esm folder and @material-ui/core/RadioGroup/useRadioGroup points to the module in the root (cjs) target.

However, if I do

import RadioGroup, { useRadioGroup }  from '@material-ui/core/RadioGroup';

Then both modules refer to the same esm module

Basically, because they refer to modules in different places, the context created on import is also different. I cannot repro this on codesandbox, but I can repro this locally. I assume codesandbox uses UMD so this problem would not be prevalent there. Got a small hole in my knowledge as I don't know exactly why it choses to go for the cjs in the first example.

@oliviertassinari

[NMinhNguyen]

I am seeing a weird situation. When I am importing the RadioGroup and useRadioGroup like this

import RadioGroup from '@material-ui/core/RadioGroup';
import useRadioGroup from '@material-ui/core/RadioGroup/useRadioGroup';

@joonarahko that works as expected, you're not supposed to import beyond the 2nd level. The second way you showed is the correct way: https://material-ui.com/guides/minimizing-bundle-size/#option-1

You may find this ESLint plugin useful (currently not published, so just paste it into your project): https://github.com/mui-org/material-ui/blob/27471b4/packages/eslint-plugin-material-ui/src/rules/restricted-path-imports.js

[joonarahko]

Ok :) Makes sense. Thanks @NMinhNguyen