extract: support TS type-aware resolution for finite dynamic keys (template unions, const maps, helper returns)

[hazem3500]

🚀 Feature Proposal

i18next-cli extract handles static literals well but misses many finite dynamic keys that are inferable from TypeScript types.

Motivation

Without built-in type-aware resolution, teams need custom TypeScript pre-pass scripts and synthetic files to extract keys that are still statically finite.

Examples of finite dynamic patterns:

• t(\${prefix}_${variant}`)wherevariant` is a string-literal union
• t(\${name}Suffix`)wherename` is a const/union
• t(getGreetingKey()) where a helper returns a finite set of literals
• t(map[type]) where map is as const

I'm aware there is extract.preservePatterns option, but it would be good to have a general extraction capability rather than hard-coding project-specific patterns.

Example

type ChangeType = 'all' | 'next' | 'this';
const t = i18next.t;

function key(): 'goodMorning' | 'goodEvening' {
  return Math.random() > 0.5 ? 'goodMorning' : 'goodEvening';
}

const map = { all: 'allAccess', next: 'nextAccess' } as const;
declare const type: ChangeType;

t(`prefix_${type}`);
t(key());
t(map[type]);

[adrai]

please try v1.49.0

[hazem3500]

Thanks for the quick fix 🙏

I'm wondering if cases like these could also be resolved as well 👇🤔

export const const ACCESS_OPTIONS = ['full', 'edit', 'restricted'] as const;

import { ACCESS_OPTIONS } from '@core/constants'

ACCESS_OPTIONS.map((option) => ({
  label: t(`${option}Access`),
}))

---

export const const ACCESS_OPTIONS = ['full', 'edit', 'restricted'] as const;
export type AccessOptions = (typeof ACCESS_OPTIONS)[number];

  import { AccessOptions } from '@core/constants'

  const [accessPreset, setAccessPreset] = useState<AccessOptions>('full');

  t(`${accessPreset}Access`)

[adrai]

Not so easy but v1.49.1 may be better...

[hazem3500]

Tested but still didn't quite handle the dynamic cases 😅

Would be awesome if the CLI was able to infer dynamic keys, would make migration way easier 😄

[adrai]

I tried to improve it a little bit more with v1.49.4...
but like said... this is not that easy... If you like feel free to try to improve it via a PR... or at least create some failing tests for your use cases.

[adrai]

@hazem3500 did you have the chance to verify the new version?