wtfd3.js

d3.js

var data = [
        [
            {
                time: new Date(2000, 1, 1),
                value: 10
            },
            {
                time: new Date(2000, 1, 2),
                value: 20
            },
            {
                time: new Date(2000, 1, 3),
                value: 30
            },
            {
                time: new Date(2000, 1, 4),
                value: 40
            }
        ], [
            {
                time: new Date(2010, 1, 1),
                value: 10
            },
            {
                time: new Date(2010, 1, 2),
                value: 20
            },
            {
                time: new Date(2010, 1, 3),
                value: 30
            },
            {
                time: new Date(2010, 1, 4),
                value: 40
            }
        ]
    ];

var paths = this.selection.data(data);
    
paths.enter()
    .append('g')
    .attr("class", "series")
    .append('path')
    .attr("class", "line");

paths.selectAll('path.line')
    .attr("d", function(d, i) {
        console.log(JSON.stringify(d), i)
        // lines is an array of line generators with different
        // scales (i.e. drawing two time series with different x scales
        // on top of each other)
        return  lines[i](d);
    });