Cytoscape - headless mode example - cytoscape.js

Question

I am unclear on how to get the headless mode (on node.js) to layout a graph and extract
the computed (per node) positioning information.
Below is the simplest example I could think of that should have worked, but doesn't.
What am I missing?
const cytoscape = require('cytoscape');
const fcose = require('cytoscape-fcose');
const elements = [
{ data: { id: 'n0' } },
{ data: { id: 'n1' } },
{ data: { id: 'n2' } },
{ data: { id: 'n3' } },
{ data: { id: 'e1', source: 'n0', target: 'n1' } },
{ data: { id: 'e2', source: 'n2', target: 'n3' } },
]
cytoscape.use(fcose); // register extension
const cy = cytoscape()
const layout = cy.layout({
name: 'fcose',
container: null,
layout: {
boundingBox: {
x1: 0,
y1: 0,
w: 600,
h: 600
},
},
elements,
headless: true,
styleEnabled: false,
animate: false,
ready: function () {
console.log(this)
}
}).run()
console.log(cy.nodes())

Answer 1

A working example:
const cytoscape = require('cytoscape');
const fcose = require('cytoscape-fcose');
const elements = [
{ data: { id: 'n0' } },
{ data: { id: 'n1' } },
{ data: { id: 'n2' } },
{ data: { id: 'n3' } },
{ data: { id: 'e1', source: 'n0', target: 'n1' } },
{ data: { id: 'e2', source: 'n2', target: 'n3' } },
]
cytoscape.use(fcose); // register extension
const cy = cytoscape({
container: null,
elements,
headless: true,
styleEnabled: false,
animate: null,
})
const layout = cy.layout({
name: 'fcose',
animate: null,
}).run()
cy.nodes().map((node, id) => {
console.log({
id,
position: node.position(),
boundingbox: node.boundingbox(),
})
})
Output:
{
id: 0,
position: { x: -10.739928259168892, y: 23.05192029205518 },
boundingbox: {
x1: -12.239928259168892,
y1: 21.55192029205518,
x2: -9.239928259168892,
y2: 24.55192029205518,
w: 3,
h: 3
}
}
{
id: 1,
position: { x: -34.115851865686764, y: -17.994146351728972 },
boundingbox: {
x1: -35.615851865686764,
y1: -19.494146351728972,
x2: -32.615851865686764,
y2: -16.494146351728972,
w: 3,
h: 3
}
}
{
id: 2,
position: { x: 34.115851865686764, y: -6.375158623550128 },
boundingbox: {
x1: 32.615851865686764,
y1: -7.875158623550128,
x2: 35.615851865686764,
y2: -4.875158623550128,
w: 3,
h: 3
}
}
{
id: 3,
position: { x: -4.785486637914051, y: -23.05192029205518 },
boundingbox: {
x1: -6.285486637914051,
y1: -24.55192029205518,
x2: -3.285486637914051,
y2: -21.55192029205518,
w: 3,
h: 3
}
}