CPU Utilization Graph

And here is Graph.js

/* Copyright (c) 2017 MrTimcakes. See the file LICENSE for copying permission. */
/*
Live graphs that update from right to left

var Graph = require("graph");
var myGraph = new Graph(90, 48);
myGraph.initData([0,1,2,3,4,5,10,15,20,2­5,30]);

function draw(){
  g.clear();
  myGraph.drawGraph(g, 5, 5);
  g.flip();
}
*/

/* Create new graph, datapoints to keep (width), height, range of data from 0 */
function Graph(historyLength, height = 64, range = 100) {
  this.history = new Int8Array(historyLength);
  this.height = height;
  this.range = range;
}

Graph.prototype.setHeight = function(height) {
  this.height = height;
};

Graph.prototype.setRange = function(range) {
  this.range = range;
};

/* Cycle all history values, add new ones to the end*/
Graph.prototype.update = function(data) {
  for (var i=1;i<this.history.length;i++){
    this.history[i-1] = this.history[i];
  }
  this.history[this.history.length-1] = data;
};

/* Replace end of history with the array given */
Graph.prototype.initData = function(data) {
  if(Array.isArray(data)){
    for (var i=0;i<data.length;i++){
      this.history[this.history.length-i] = data[data.length-i];
    }
  }
};

/* Draw axis, the convert each value to a y and plot */
Graph.prototype.drawGraph = function(g, x, y) {
  g.drawLine(x, y, x, y+this.height);
  g.drawLine(x, y+this.height, x+this.history.length, y+this.height);

  g.moveTo(x, (y - (this.height/this.range)*this.history[0]­) + this.height);
  for (i=1;i<this.history.length;i++){
    g.lineTo(x+i, (y - (this.height/this.range)*this.history[i]­) + this.height);
  }
};

exports = Graph;