Creating nested JS maps dynamically via a loop

Question

The following code creates a nested JS map. It works already:

let a = data[0];
let b = data[1];
let c = data[2];
    
myMap.set(a, myMap.get(b) || new Map());
myMap.get(a).set(b, myMap.get(a).get(b) || new Map());
myMap.get(a).get(b).set(c, myMap.get(a).get(b).get(c) || new Map());

There can be many more variables than just a, b, c ... I'm wondering if there is a possibility to do the same via a loop (or another more tiny code)

I think a solution may be to create the method chains myMap.get(a).get(b).get(c) ... dynamically But I'm not sure wether this is possible, since eval is not a good solution.

score 0 · Accepted Answer · answered Oct 25 '22 at 13:50

Not sure if I understand your exact requirement, but you can do something like this

const getNestedMap = (variables) => {
    const map = new Map();
    let temp = map;
    variables.forEach((variable) => {
        if (!temp.has(variable)) {
            temp.set(variable, new Map())
        }

        temp = temp.get(variable)
    })

    return map
};

And then call the function with an array of required variables

getNestedMap([a, b, c]);

Creating nested JS maps dynamically via a loop

1 Answers1