[Solved]-parallel links between nodes-d3.js

Update: position of the Links need to be calculated by new radian considering offset, like:

let parent = connection.parent;

const sx = parent.source.x;
const sy = parent.source.y;
const tx = parent.target.x;
const ty = parent.target.y;
const radiusSource = parent.source.radius;
const radiusTarget = parent.target.radius;

let radian = Math.atan2(ty - sy, tx - sx);
let offset = 0.1 // Offset ratio of radian, can be adjusted
let offsetRadian;

let angle = radian * 180 / Math.PI;
let opposite = Math.abs(angle) > 90;
if (opposite) {
    angle -= 180;
    offsetRadian = radian * (1 + offset);
} else {
    offsetRadian = radian * (1 - offset);
}

let x1 = sx + Math.cos(offsetRadian) * radiusSource;
let y1 = sy + Math.sin(offsetRadian) * radiusSource;

let x2 = tx - Math.sin(offsetRadian) * radiusTarget;
let y2 = ty - Math.cos(offsetRadian) * radiusTarget;

connection.coords = [x1, y1, x2, y2, angle, opposite];
return connection.coords;