How to dynamically create multiPolygons Arrays?

Question

My goal is to build a turf.js multiPolygon. This kind of hard-coding is working fine:

const searchWithin = turf.multiPolygon(
[
    [[
        [-0.607051, 44.840753], 
        [-0.543708, 44.832962], 
        [-0.52225, 44.820544], 
        [-0.566367, 44.808853], 
        [-0.586367, 44.788853], 
        [-0.607051, 44.840753]
    ]],
    [[
        [5.39014, 43.279295], 
        [5.393069, 43.279249], 
        [5.391814, 43.278421], 
        [5.390709, 43.278749], 
        [5.3909, 43.2785], 
        [5.39014, 43.279295]
    ]]
]);

As you can see, there is 3 levels of brackets before getting the coordinates arrays. Coming from the database, I am getting:

[
    [
        [-0.607051, 44.840753], 
        [-0.543708, 44.832962], 
        [-0.52225, 44.820544], 
        [-0.566367, 44.808853], 
        [-0.586367, 44.788853], 
        [-0.607051, 44.840753]
    ],
    [
        [5.39014, 43.279295], 
        [5.393069, 43.279249], 
        [5.391814, 43.278421], 
        [5.390709, 43.278749], 
        [5.3909, 43.2785], 
        [5.39014, 43.279295]
    ]
]

To get data from the Database:

.subscribe((response) => {
      this.locations = response;
      this.polygonsArray.push(this.locations);
      this.locations.forEach(element => {          
this.polygons.push(element.geoDefinition.features['0'].geometry.coordinates);

with polygons declared as:

polygons: number[][][] = [];

I tried:

this.polygons.push('['+element.geoDefinition.features['0'].geometry.coordinates)+']';

but coordinates are numbers so I cannot concatenate.

How could I do to have this structure with 3 square-brackets, please? Any help would be very helpful.

I thank you in advance for your help.

Answer 1

It is not clear about expected structure. But first notable things are:

1. If polygons are 3 dimension array like polygons: number[][][] = [];, you can't push number directly to it, like polygons.push(5), you have to take into account structure:

polygons[0][0].push(5) or polygons.push([[5]]);

2. Another thing is this.polygonsArray.push(this.locations); - it should be at least this.polygonsArray.push(...this.locations); as push would add entire this.locations array as first element of this.polygonsArray.

3. And the last. If you push something like this.polygons.push('['+something+']'); - you just push a string to the simple array. Instead of that you can use

   this.polygons[0].push(something);

Hope it can provide some ideas how to organize 3-dimensional structure in your case.