JSFiddle - React, Tailwind, and code Playground

CSS

.bar {
  fill: steelblue;
}

.bar:hover {
  fill: brown;
}

JavaScript

var arr1 = [0,1, 2, 3, 4, 5, 6];
    var arr2 = [839, 149, 146, 200, 200, 121, 63];

function mergingAr (array1, array2)
{
    var i, out = [];//literal new array
    for(i=0;i<array1.length;i++)
    {
        out.push([array1[i],array2[i]]);
    }
    out = out.sort(function(a,b) { return d3.ascending(a[0],b[0]) })
    return out;
}

var data = mergingAr(arr1, arr2);
    margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;


   var x = d3.scale.linear()
          .domain([0, d3.max(data, function(d) { 
          return d[0]; })])
          .range([0, width]);


   var y = d3.scale.linear()
      .domain([0, d3.max(data, function(d) { return d[1]; })])
      .range([height, 0]);


var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left");

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");



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

  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis)
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", ".71em")
      .style("text-anchor", "end")


  svg.selectAll(".bar")
      .data(data)
      .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x(d[0]); })
      //.attr("width", x.rangeBand())
  .attr("width", function(d,i){
      if(i!=(data.length-1)) {
          return x(data[i+1][0])-x(data[i][0])
      } else {
          return 10;
      }
  })
      .attr("y", function(d) { return y(d[1]); })
      .attr("height", function(d) { return height - y(d[1]); });

function type(d) {
 d[1] = +d[1];
...