Streaming in JavaScript

How to create D3.js-based streaming plots in Plotly.js.

New to Plotly?

Plotly is a free and open-source graphing library for JavaScript. We recommend you read our Getting Started guide for the latest installation or upgrade instructions, then move on to our Plotly Fundamentals tutorials or dive straight in to some Basic Charts tutorials.

Basic Streaming

function rand() {
  return Math.random();
}

Plotly.newPlot('myDiv', [{
  y: [1,2,3].map(rand),
  mode: 'lines',
  line: {color: '#80CAF6'}
}]);

var cnt = 0;

var interval = setInterval(function() {

  Plotly.extendTraces('myDiv', {
    y: [[rand()]]
  }, [0])

  if(++cnt === 100) clearInterval(interval);
}, 300);

Multiple Traces

function rand() {
  return Math.random();
}

Plotly.newPlot('myDiv', [{
  y: [1,2,3].map(rand),
  mode: 'lines',
  line: {color: '#80CAF6'}
}, {
  y: [1,2,3].map(rand),
  mode: 'lines',
  line: {color: '#DF56F1'}
}]);

var cnt = 0;

var interval = setInterval(function() {

  Plotly.extendTraces('myDiv', {
    y: [[rand()], [rand()]]
  }, [0, 1])

  if(++cnt === 100) clearInterval(interval);
}, 300);

Streaming with Timestamp

function rand() {
  return Math.random();
}

var time = new Date();

var data = [{
  x: [time],
  y: [rand()],
  mode: 'lines',
  line: {color: '#80CAF6'}
}]


Plotly.newPlot('myDiv', data);

var cnt = 0;

var interval = setInterval(function() {

  var time = new Date();

  var update = {
  x:  [[time]],
  y: [[rand()]]
  }

  Plotly.extendTraces('myDiv', update, [0])

  if(++cnt === 100) clearInterval(interval);
}, 1000);

Extend Traces & Relayout

function rand() {
  return Math.random();
}

var time = new Date();

var data = [{
  x: [time],
  y: [rand],
  mode: 'lines',
  line: {color: '#80CAF6'}
}]

Plotly.newPlot('myDiv', data);

var cnt = 0;

var interval = setInterval(function() {

  var time = new Date();

  var update = {
  x:  [[time]],
  y: [[rand()]]
  }

  var olderTime = time.setMinutes(time.getMinutes() - 1);
  var futureTime = time.setMinutes(time.getMinutes() + 1);

  var minuteView = {
        xaxis: {
          type: 'date',
          range: [olderTime,futureTime]
        }
      };

  Plotly.relayout('myDiv', minuteView);
  Plotly.extendTraces('myDiv', update, [0])

  if(++cnt === 100) clearInterval(interval);
}, 1000);

30 Points Using Update

var arrayLength = 30
var newArray = []

for(var i = 0; i < arrayLength; i++) {
  var y = Math.round(Math.random()*10) + 1
  newArray[i] = y
}

Plotly.newPlot('myDiv', [{
  y: newArray,
  mode: 'lines',
  line: {color: '#80CAF6'}
}]);

var cnt = 0;

var interval = setInterval(function() {

  var y = Math.round(Math.random()*10) + 1
  newArray = newArray.concat(y)
  newArray.splice(0, 1)

  var data_update = {
    y: [newArray]
  };

  Plotly.update('myDiv', data_update)

  if(++cnt === 100) clearInterval(interval);
}, 1000);

Streaming Subplots

function rand() {
  return Math.random();
}

var time = new Date();

var trace1 = {
  x: [],
  y: [],
  mode: 'lines',
  line: {
    color: '#80CAF6',
    shape: 'spline'
  }
}

var trace2 = {
  x: [],
  y: [],
  xaxis: 'x2',
  yaxis: 'y2',
  mode: 'lines',
  line: {color: '#DF56F1'}
};

var layout = {
  xaxis: {
    type: 'date',
    domain: [0, 1],
    showticklabels: false
  },
  yaxis: {domain: [0.6,1]},
  xaxis2: {
    type: 'date',
    anchor: 'y2',
    domain: [0, 1]
  },
  yaxis2: {
    anchor: 'x2',
    domain: [0, 0.4]},
}

var data = [trace1,trace2];

Plotly.newPlot('myDiv', data, layout);

var cnt = 0;

var interval = setInterval(function() {

  var time = new Date();

  var update = {
    x: [[time], [time]],
    y: [[rand()], [rand()]]
  }

  Plotly.extendTraces('myDiv', update, [0,1])

  if(++cnt === 100) clearInterval(interval);
}, 1000);