JSFiddle - React, Tailwind, and code Playground

HTML

<pre id="tsvdata">
x0	y0	x1	y1	x2	y2	weight
0.5	0.5	0.2	0.2			2
0.25	0.35	0.7	0.8	0.7	0.6	1
</pre>

CSS

#tsvdata {
    display: none;
}

JavaScript

var raw = d3.select("#tsvdata").text();
var data = d3.tsv.parse(raw);

var width = 500;
var height = 500;

var x = d3.scale.linear().range([0, width]);
var y = d3.scale.linear().range([0, height]);

var svg = d3.select("body")
        .append("svg")
        .attr("width", width)
        .attr("height", height);

var line = d3.svg.line();

data.forEach(function(d) {
    d.points = [];
    for (var i = 0; d["x"+i] !== "" && (typeof d["x"+i] !== 'undefined'); i++) {
        d.points.push([x(d["x"+i]), y(d["y"+i])]);
    }
});

svg.selectAll("path")
    .data(data)
    .enter()
    .append("path");

svg.selectAll("path")
    .attr("d", function(d) { return line(d.points); })
    .attr("stroke-width", function(d) { return (d.weight); })
    .attr("stroke", "black")
    .attr("fill", "none");