aborted lbs (tried to zoom)

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.area {
  fill: none;
  clip-path: url(#clip);
}

.line {
    fill: MidnightBlue;
    stroke: 2px;
  }
 .grid line {
    stroke: lightgrey;
    stroke-opacity: 0.6;
    shape-rendering: crispEdges
  }
</style>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var svg = d3.select("svg"),
    margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom;

var parseDate = d3.timeParse("%d-%b-%y");
  var formatTime = d3.timeFormat("%e %b %y");

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

var xAxis = d3.axisBottom(x),
    yAxis = d3.axisLeft(y);

var zoom = d3.zoom()
    .scaleExtent([1, 32])
    .translateExtent([[0, 0], [width, height]])
    .extent([[0, 0], [width, height]])
    .on("zoom", zoomed);

svg.append("defs").append("clipPath")
    .attr("id", "clip")
  .append("rect")
    .attr("width", width)
    .attr("height", height);

var g = svg.append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

function make_x_gridlines() {
    return d3.axisBottom(x)
    	.ticks(20)
  }
function make_y_gridlines() {
    return d3.axisLeft(y)
    	.ticks(12)
  }
  
d3.tsv("myLbs.tsv", type, function(error, data) {
  if (error) throw error;

x.domain(d3.extent(data, function(d) { return d.date; }));
  y.domain([200, d3.max(data, function(d) { return d.lbs; })]);

svg.append("g")
  		.attr("class","grid")
  		.attr("transform","translate(0," + height + ")")
  		.style("stroke-dasharray",("3,3"))
  		.call(make_x_gridlines()
            .tickSize(-height)
            .tickFormat("")
            )

svg.append("g")
  		.attr("class","grid")
  		.style("stroke-dasharray",("3,3"))
  		.call(make_y_gridlines()
            .tickSize(-width)
  .tickFormat("")
            )
 svg.append('path')
	.data([data])
	.attr('class','line')
	.attr('d',valueline)

g.append("g")
      .attr("class", "axis axis--x")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);

g.append("g")
      .attr("class", "axis axis--y")
      .call(yAxis);

});

function zoomed() {
  var t = d3.event.transform, xt = t.rescaleX(x);
  g.select(".line").attr("d", line.x(function(d) { return xt(d.date); }));
  g.select(".axis--x").call(xAxis.scale(xt));
}

function type(d) {
  d.date = parseDate(d.date);
  d.price = +d.lbs;
  return d;
}

</script>

https://d3js.org/d3.v4.min.js