Labels

const edgeData = {
    '1-2': [4.5, 420],
    '1-3': [3.8, 730],
    '2-3': [2.9, 180],
    '2-4': [6.2, 940],
    '3-4': [9,3, 550],
    '3-5': [1.4, 380],
    '4-5': [2.7, 290]
}

canvas.nodes([1, 2, 3, 4, 5]).add()

const edges = Object.keys(edgeData).map(k => k.split('-'))
canvas.edges(edges).data(Object.values(edgeData)).add({
    labels: d => ({
        1: { color: 'red', text: d[0] },
        2: { color: 'blue', text: d[1] }
    })
})