Office Addin: Excel Depth First Search - excel

Question

tl;dr I am having problems with executing a recursive function on an Excel sheet. I will provide as much detail to my problem below as possible but I would appreciate a simple, working async recursive example unrelated to the specific domain/problem I am trying to solve as that might be easier
Problem Context
I am trying to build an add in (task pane) in order to linearize multi-variable analysis (i.e. what if analysis) and constraint solving in spread sheets. My hypothesis is that the inherently two dimensional grid of spreadsheets doesn't scale well as the number of variables grow. I would like to try to surface this functionality through an integrated query language.
Because Excel doesn't allow me to tap into it's interpreter, I need to copy the chain of formulas to cells that are out of view, run my computations there and then copy the results to where the user wants them.
This requires me to recursively explore the formula in question and copy all the nested formulas that may be effected by the variables in question.
For example if I have the following structure.
A7 -> IF(A5>0, A4, A3)
A5 -> A1 + A2
A4 -> A1 + 10
A3 -> A2 + 10
A1 -> 10
A2 -> 20
I start at the target formula and explore the formulas and copy them to a new location. As I copy them, I build a new environment that tell me where to look. i.e.
IF(A5>0, A4, A3)
-- A5
-- A1
-- A2
copy(A5, copyTo = B5, env(A5 -> B5))
-- A4
-- A1
copy(A4, copyTo = B4, env(A5 -> B5, A4 -> B4))
-- A3
-- A2
copy(A3, copyTo = B3, env(A5-> B5, A4-> B4))
new_formula = replaceCells(A7, env) // this will return IF(B5>0, B4, B3)
copy(A7, copyTo=B7, env)
So tl;dr is it's depth first search + environment accumulation, which is normally very simple to do
Actual Problem
However I am having a difficult time wrapping my head around Officejs's concurrency model. Because each recursive call gets executed asynchronously, mutating the environment becomes problematic (while there aren't any race conditions here, the bindings from each depth needs to be present at the time of execution of the one above to allow for correct rewriting
When my first call to this function returns unfortunately a lot of the bindings are missing. I tried solving this issue with both async/await and the Promise API to no result. What is the proper way of going about this? (I am 100% sure this is a concurrency issue. Not only it makes sense but this code works in Google AppScript, where the concurrency model is much more limited).
P.S. You might ask, "if you want this to execute sequentially, why is it async?" -> It's because I need to load in the formulas in the target cell which requires me to sync the context.
P.S. 2: I have also read Avoid using the context.sync method in loops but can't seem to find a way around it.
async function exploreAndCopy(
context: Excel.RequestContext,
currentWorksheet : Excel.Worksheet,
source: string,
target : string,
row : string,
column : number,
env: Map<string, string>) {
let rx = currentWorksheet.getRange(target);
rx.load()
await context.sync();
let cellFormulas = rx.formulas;
if (cellFormulas.length > 0){
var f : string = cellFormulas[0][0]
var newFormula = f.replace(source, "A29")
//Get the referenced cells
let cells : string[] = newFormula.split(/[^A-Za-z0-9]/)
cells = cells.filter(s => s.match(/^(?=.*[a-zA-Z])(?=.*[0-9])/));
//remove dublicates
cells = cells.filter((item, index) => cells.indexOf(item) === index);
for(var c of cells){
// ATTEMP #1
await exploreAndCopy(context, currentWorksheet, source, c, row, column + 1 + cells.indexOf(c), env)
// ATTEMPT #2
exploreAndCopy(context, currentWorksheet, source, c, row, column + 1 + cells.indexOf(c), env).then( p =>
env.forEach((value: string, key: string) => {
newFormula = newFormula.replace(key, value)
})
); // will mutate the env
// Also tried Promises.all
await context.sync();
}
}
await context.sync();
//replace everything in the map
var finalFormula = newFormula
env.forEach((value: string, key: string) => {
finalFormula = finalFormula.replace(key, value);
});
//set env
env.set(target, row + column)
//override
var targetCell = currentWorksheet.getRange(row + column)
targetCell.formulas = [[finalFormula]]
}
Appreciate any recommendations you might have