[FEAT] Downlevel the lowest TS version needed to integrate bpmn-visualization

[tbouffard]

Is your feature request related to a problem? Please describe. Until recently, we didn't explicitly explained what was the lowest TypeScript version. See #2246 In addition, the current ([email protected]) lowest TypesScript version is 4.5, which is quite recent (less than a year) and this requirement cannot be met by some project (see #2221).

Describe the solution you'd like Generate types that can be used by older TypeScript version. Version 4.0 was released 2 years ago, so we can consider to support only v4+ version safely. Currently, [email protected] depends on [email protected] which depends on TypeScript 4.1.3. So we could support TS 4.3+ for instance (to have override keywords).

We are not forced to change the source code: we can use tool like https://github.com/sandersn/downlevel-dts Notice that after implementing #2231, some imports using 4.5 types features may be dropped in the final type file. So, the TS version may be down-leveled as a consequence.

Describe alternatives you've considered If we don't down-level the TS version, some projects cannot use bpmn-visualization.

Additional context TypeScript release dates

• 4.8 August 25th, 2022 https://devblogs.microsoft.com/typescript/announcing-typescript-4-8/
• 4.7 May 24th, 2022 https://devblogs.microsoft.com/typescript/announcing-typescript-4-7/
• 4.6 February 28th, 2022 https://devblogs.microsoft.com/typescript/announcing-typescript-4-6/
• 4.5 November 17th, 2021 https://devblogs.microsoft.com/typescript/announcing-typescript-4-5/
• 4.4 August 26th, 2021 https://devblogs.microsoft.com/typescript/announcing-typescript-4-4/
• 4.3 May 26th, 2021 https://devblogs.microsoft.com/typescript/announcing-typescript-4-3/
• 4.2 February 23rd, 2021 https://devblogs.microsoft.com/typescript/announcing-typescript-4-2/
• 4.1 November 19th, 2020 https://devblogs.microsoft.com/typescript/announcing-typescript-4-1/
• 4.0 August 20th, 2020 https://devblogs.microsoft.com/typescript/announcing-typescript-4-0/