D3 Playground

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:50px;right:50px;bottom:0;left:50px; }
        svg {
      width: 100%;
      height: 100%;
    }
  </style>
</head>

<body>
  <svg>
  </svg>
  <script>
    // Feel free to change or delete any of the code you see in this editor!
    const data = [200, 150, 200, 300, 325, 200],
          rectWidth = 50,
          height = 300;
    
    const svg = d3.select('svg');
    const currentSelection = svg.selectAll('rect')
    	.data(data)
      .enter().append('rect')
     	.attr('x', (d, i) => i * rectWidth)
    	.attr('y', d => height - d)
    	.attr('width', rectWidth)
    	.attr('height', d => d)
      .attr('fill', 'blue')
    	.attr('stroke', '#fff')
      .attr('transform', 'translate(40,20)');  
   
    
    //Addressing the issue of making things fit on the screen
    //eg super small values or large humonguous values that go off-screen
    
 		const extent = d3.extent(data, d => d);
   	console.log(extent);
    
    const yScale = d3.scaleLinear()
    	.domain(extent) //input
    	.range([height, 0]) //output
  
   	//Now I need to do scale axis
    const yAxis = d3.axisLeft()
    .scale(yScale);
    
    d3.select('svg')
    	.append('g')
    	.attr('transform', 'translate(40,20)')
    	.call(yAxis);
    
    /*
    const data = [100, 200, 250, 125, 175]
    const rectWidth = 50;
    const height = 300;
    d3.selectAll('rect')
    	.data(data)
    	.attr('x', (d, i) => i * rectWidth)
    	.attr('y', d => height - d)
    	.attr('width', rectWidth)
    	.attr('height', d => d)
      .attr('fill', 'blue')
    	.attr('stroke', '#fff');  
      
      */
  </script>
</body>

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