how to calculate flows in pipe network in javascript

index.tsx
// Sample Calculation

// Define inputs
const nodes = [
  { id: 1, demand: -2, elevation: 340 },
  { id: 2, demand: 4, elevation: 330 },
  { id: 3, demand: -2, elevation: 320 },
];
const pipes = [
  { id: 1, fromNode: 1, toNode: 2, length: 1000, diameter: 0.6, roughness: 0.03 },
  { id: 2, fromNode: 2, toNode: 3, length: 800, diameter: 0.6, roughness: 0.03 },
  { id: 3, fromNode: 1, toNode: 3, length: 1200, diameter: 0.6, roughness: 0.03 },
];

// Define constants
const rho = 1000; // density of fluid in kg/m^3
const g = 9.81; // gravitational acceleration in m/s^2
const maxIter = 1000; // maximum number of iterations
const tolerance = 0.001; // tolerance for convergence

// Initialize the unknowns
pipes.forEach(pipe => pipe.flow = 0);

// Define the functions to calculate flow and head loss
function flowRate(p, q, k) {
  return (p - q) / k;
}

function headLoss(L, D, f, q) {
  const v = q / (Math.PI * D * D / 4); // velocity in m/s
  const relRough = D * f / 8 / L;
  const hf = relRough * v * v / 2 / g; // head loss in m
  return hf;
}

// Run the Hardy-Cross method
let iter = 0;
let maxError = tolerance + 1;
while (iter < maxIter && maxError > tolerance) {
  console.log('Iteration', iter + 1);

  // Calculate head loss at each pipe with guessed flows
  pipes.forEach(pipe => {
    const fromNode = nodes.find(node => node.id == pipe.fromNode);
    const toNode = nodes.find(node => node.id == pipe.toNode);
    const p = fromNode.elevation;
    const q = toNode.elevation;
    const q1 = pipe.flow;
    const q2 = flowRate(p, q, pipe.diameter, pipe.roughness, q1);
    const hf = headLoss(pipe.length, pipe.diameter, pipe.roughness, q2);
    pipe.headLoss = hf;
    console.log(`Pipe ${pipe.id}: flow=${q2.toFixed(3)}, hl=${hf.toFixed(3)}`);
  });

  // Calculate the flow corrections for each pipe
  maxError = 0;
  pipes.forEach(pipe => {
    let correction = 0;
    pipes.forEach(pipe2 => {
      if (pipe2.id != pipe.id) {
        const factor = (pipe.fromNode == pipe2.fromNode || pipe.fromNode == pipe2.toNode) ? 1 : -1;
        correction += factor * pipe2.headLoss;
      }
    });
    correction /= pipe.headLoss;
    const tempFlow = pipe.flow + correction;
    const error = Math.abs(tempFlow - pipe.flow);
    pipe.flow = tempFlow;
    if (error > maxError) maxError = error;
  });
  console.log('Max Error', maxError.toFixed(3));

  iter++;
}

// Output the results
console.log('Results:');
pipes.forEach(pipe => console.log(`Pipe ${pipe.id}: flow=${pipe.flow.toFixed(3)}`));
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