Feature Request: Support Functional Accessors for nodeRelSize

[ProtDos]

Problem

nodeRelSize currently only accepts a static number:

graph.nodeRelSize(4);

This makes it impossible to size nodes dynamically based on node data. Other APIs like nodeColor already support function accessors.

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Desired Usage

Allow nodeRelSize to accept a function:

graph.nodeRelSize(node => node.importance || 4);

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Required Changes

1. README
   Update documentation to indicate nodeRelSize accepts ([num or fn])
   https://github.com/vasturiano/force-graph/blob/master/README.md#L99

2. Core logic
   Update nodeRelSize to use an accessor function
   https://github.com/vasturiano/force-graph/blob/master/src/force-graph.js#L306

3. Canvas renderer
   Apply the same accessor logic here:

   • https://github.com/vasturiano/force-graph/blob/master/src/canvas-force-graph.js#L178
   • https://github.com/vasturiano/force-graph/blob/master/src/canvas-force-graph.js#L325-L326

[vasturiano]

@ProtDos thanks for reaching out.

If you need to give nodes different sizes, you should do it with the accessor function .nodeVal(node => ...).

The nodeRelSize is merely a static multiplier of the varying nodeVal to allow you to scale all the node surface areas up/down as a whole.