D3 json stock chart not displaying

问题

Can't seem to properly fetch the data from JSON. My chart is not even able to be displayed. Any ideas on how i can fix this?

    <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: 50},
        width = +svg.attr("width") - margin.left - margin.right,
        height = +svg.attr("height") - margin.top - margin.bottom,
        g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

    var parseTime = d3.timeParse("%d-%b-%y");

    var x = d3.scaleTime()
        .rangeRound([0, width]);

    var y = d3.scaleLinear()
        .rangeRound([height, 0]);

    var line = d3.line()
        .x(function(d) { return x(d.timeStr); })
        .y(function(d) { return y(d.bid); });

    d3.json("bboList.json", function(d) {
      d.timeStr = parseTime(d.timeStr);
      d.bid = +d.bid;
      return d;
    }, function(error, data) {
      if (error) throw error;

      x.domain(d3.extent(data, function(d) { return d.timeStr; }));
      y.domain(d3.extent(data, function(d) { return d.bid; }));

      g.append("g")
          .attr("transform", "translate(0," + height + ")")
          .call(d3.axisBottom(x))
        .select(".domain")
          .remove();

      g.append("g")
          .call(d3.axisLeft(y))
        .append("text")
          .attr("fill", "#000")
          .attr("transform", "rotate(-90)")
          .attr("y", 6)
          .attr("dy", "0.71em")
          .attr("text-anchor", "end")
          .text("Price ($)");

      g.append("path")
          .datum(data)
          .attr("fill", "none")
          .attr("stroke", "steelblue")
          .attr("stroke-linejoin", "round")
          .attr("stroke-linecap", "round")
          .attr("stroke-width", 1.5)
          .attr("d", line);
    });

    </script>

Notes:

• The ask and bid of bboList, and the price of tradeList are in hundreds of pennies so 233200 --> $23.32

• The time in tradeList is in nanoseconds so 34574353918784 --> 09:36:14.353

  {"bboList":[{"ask":235400,"bid":231800,"timeStr":"09:30:00.000"},
      {"ask":235400,"bid":230900,"timeStr":"09:30:07.819"},
      {"ask":238300,"bid":230900,"timeStr":"09:30:07.819"},
      {"ask":238300,"bid":227500,"timeStr":"09:30:26.786"},
      ...
  

回答1:

d3.json does not accept an accessor (or row) function. It has to be just:

d3.json(url[, callback])

In your code:

d3.json("bboList.json", function(d) {
    d.timeStr = parseTime(d.timeStr);
    d.bid = +d.bid;
    return d;
}, function(error, data) {
    if (error) throw error;
    //...
});

Everything between the URL and function(error, data) is the row function.

Solution: remove it, and coerce the values to numbers and dates using a forEach:

d3.json("bboList.json", function(error, data) {
    if (error) throw error;

    data.forEach(d => {
        d.timeStr = parseTime(d.timeStr);
        d.bid = +d.bid;
    });

    /...
});

来源：https://stackoverflow.com/questions/42475033/d3-json-stock-chart-not-displaying