Saving an edited Graph as Mermaid / AST manipulation

[v4dkou]

Is your feature request related to a problem? Please describe.
There are cases when diagram definitions get outdated in a way that's predictable enough to warrant automated updates of them.

For instance, we use Gantt diagrams to pre-plan projects. If the start date of a project is postponed for whatever reason, we need to shift all dates for milestones by a specified amount of time.

Describe the solution you'd like
Ideally, I would write a script that parses Mermaid definitions, processes them and saves back, but I haven't found such an API in Mermaid.

Describe alternatives you've considered
As of now, for shifting a Gantt diagram, I look for dateFormat and use RegEx to find strings according to the pattern.

However, this could be error-prone (for instance, if dates are also included in comments to refer to some specific date).
Also, if I am ever to write more scripts for Mermaid manipulation, I would like to have a unified API, rather than inventing tricks for each scenario.