Convert punctuateSeries to TypeScript

[vtejasri1511-sudo]

Partially addresses #3533

Changes proposed in this pull request:

• Converted framework/core/js/src/common/helpers/punctuateSeries from JavaScript to TypeScript.
• No behavior or API changes intended; this is a small isolated step in the ongoing core JS → TS migration.

Reviewers should focus on:

• Confirm logic is unchanged (only typing / file extension change).
• Confirm TS types (mithril Children) are appropriate and build tooling accepts the new .ts file.

Screenshot
N/A (no user-facing change)

[imorland]

Good first contribution — the migration is on the right track and the logic is correct. A few things need addressing before merge.

Logic equivalence ✅
The new for loop produces identical output to the original .reduce().slice(0,-1) chain. Both correctly build [item, glue, item, ...] without a trailing glue. The refactor is actually clearer.

Return type concern
trans() with parameters is typed as any[], not Children. The cast as Children on the glue variable silences a type error rather than reflecting the actual types involved. The return type Children on the function itself is fine (it matches the existing .d.ts), but the as Children assertion is a sign the types aren't quite right.

Default parameter
Adding = [] as a default is a minor API change. The existing call sites always pass the array, but it does change the observable signature. Not a blocker, but worth noting.

[imorland]

The function-level JSDoc describing the purpose and example has been removed. Since dist-typings is generated from this file, that documentation will be lost for extension authors browsing the .d.ts declarations. Restore the description and @example from the original .js file:

/**
 * The `punctuateSeries` helper formats a list of strings (e.g. names) to read
 * fluently in the application's locale.
 *
 * ```js
 * punctuateSeries(['Toby', 'Franz', 'Dominion']) // Toby, Franz, and Dominion
 * ```
 */

[imorland]

The items parameter has a default of []. The original function required an argument. While defensive, this is a subtle API change — callers passing undefined will now silently get [] back. Since all current call sites pass the array explicitly, consider dropping the default to keep the types tight:

export default function punctuateSeries(items: Children[]): Children {

[imorland]

trans() with parameters returns any[] (see Translator.tsx overloads), not Children. The as Children assertion is masking an underlying type mismatch rather than resolving it.

The simplest correct approach is to type glue as any[]:

const glue = app.translator.trans('core.lib.series.glue_text') as any[];

Or, since the translator returns the rendered translation here, you can just use any and let the array push accept it — or keep as Children with a comment explaining why. Either way, a note clarifying the intentional cast would help reviewers.

[imorland]

Good first contribution — the migration is on the right track and the logic is correct. A few things need addressing before merge.

Logic equivalence ✅
The new for loop produces identical output to the original .reduce().slice(0,-1) chain. Both correctly build [item, glue, item, ...] without a trailing glue. The refactor is actually clearer.

Return type concern
trans() with parameters is typed as any[], not Children. The cast as Children on the glue variable silences a type error rather than reflecting the actual types involved. The return type Children on the function itself is fine (it matches the existing .d.ts), but the as Children assertion is a sign the types aren't quite right.

Default parameter
Adding = [] as a default is a minor API change. The existing call sites always pass the array, but it does change the observable signature. Not a blocker, but worth noting.

[imorland]

The function-level JSDoc describing the purpose and example has been removed. Since dist-typings is generated from this file, that documentation will be lost for extension authors browsing the .d.ts declarations. Restore the description and @example from the original .js file:

/**
 * The `punctuateSeries` helper formats a list of strings (e.g. names) to read
 * fluently in the application's locale.
 *
 * ```js
 * punctuateSeries(['Toby', 'Franz', 'Dominion']) // Toby, Franz, and Dominion
 * ```
 */

[imorland]

trans() with parameters is typed as any[] (see Translator.tsx overloads), not Children. The cast as Children is masking an underlying type mismatch rather than resolving it.

The simplest correct approach is to type glue as any[]:

const glue = app.translator.trans('core.lib.series.glue_text') as any[];

Or keep as Children but add a comment explaining the intentional cast so reviewers understand it's deliberate.