await for getClusterLeaves

[transfluxus]

Motivation

basically described here:
#8613

I want to run over a bunch of clusters make some calculation over their leaves and then set the data of a source. Having a callback in the middle for all clusters makes the whole procedure hard

Design Alternatives

have an await for getClusterLeaves

Design

getClusterLeaves with Promise a basically because Callbacks should be dead

Mock-Up

source_layer.getClusterLeaves(cluster_id, cluster.properties.point_count, 0).then(leaves => {}).catch(err => {}) ....

leaves = await source_layer.getClusterLeaves(cluster_id, cluster.properties.point_count, 0)

Concepts

Promises, many JS developer know promises by now

[mourner]

Duplicate of #3964

[hmendezm]

I am not able to await getClusterleaves. Can someone give an example of how I can wait for the getClusterLeaves? I need to have the leaves before continue running the next code

await clusterSource.getClusterLeaves(clusterId, total, 0, function (err, aFeatures) {
that._clusterLeaves = aFeatures;
});
console.log(that._clusterLeaves );

[vchrisb]

In my case I created a vue method to wrap the callback based function with a Promise:

getClusterLeaves(cluster_id, limit, offset) {
  return new Promise((resolve, reject) => {
    this.map.getSource('locations').getClusterLeaves(cluster_id, limit, offset, (err, features) => {
      if (err) reject(err);
      else resolve(features);
    });
  });
};

this could then be used by:

await this.getClusterLeaves(feature.properties.cluster_id, feature.properties.point_count, 0);