CS 529 Visual Data Science Tutorial: Interaction in D3.js / Naveen Kumar Sangi

// Add a title element inside the element to be annotated

// Try to move your mouse over the Pokeball and the button on it!

html`

<title>I'm a Pokeball!</title>

</circle>

<title>What's inside!?</title>

</circle>

</svg>

`

// D3.js is built on top of SVG, so it is very similar to the SVG example

// Try to move your mouse over the circle above!

{

const height = 60

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 30, top: 10, right: 10, bottom: 20 }

svg.selectAll('circle')

.data([{ x: 30, y: 30, r: 30, title: 'Details on demand!' }])

.enter()

.append('circle')

.attr('cx', d => d.x)

.attr('cy', d => d.y)

.attr('r', d => d.r)

.attr('fill', 'SteelBlue')

// Append a title element inside the circle

.append('title')

// It can be multilined, but becareful with the indentation

.text(d => `${d.title}

cx: ${d.x}

cy: ${d.y}

r: ${d.r}`)

return svg.node()

}

// Variable to demonstrate mouseover and mouseout events

mutable hovering = 'None'

// Try to move your mouse over the circles above!

{

const height = 60

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 30, top: 10, right: 10, bottom: 20 }

const data = [

{ x: 30, y: 30, r: 30, title: 'I am the 1st circle!' },

{ x: 90, y: 30, r: 30, title: 'I am the 2nd circle!' },

{ x: 150, y: 30, r: 30, title: 'I am the 3rd circle!' },

{ x: 210, y: 30, r: 30, title: 'I am the 4th circle!' }

]

svg.selectAll('circle')

.data(data)

.enter()

.append('circle')

.attr('cx', d => d.x)

.attr('cy', d => d.y)

.attr('r', d => d.r)

.attr('fill', 'SteelBlue')

// Listen to the "mouseover" event, and set the value of "hovering" and change the color

.on('mouseover', function (d, i) {

mutable hovering = data[i].title

d3.select(this)

.attr('opacity', 0.5)

})

// Listen to the "mouseout" event, and reset the value of "hovering" and color

.on('mouseout', function (d, i) {

mutable hovering = 'None'

d3.select(this)

.attr('opacity', 1)

})

return svg.node()

}

// Variable to reflect the clicking, change its value in your code below!

mutable clicked = "None"

/******************************************************************************

* TODO: *

* Try to replace the "mouseover" event to "click" event, and change the *

* value of the "clicked" variable! *

******************************************************************************/

{

const height = 60

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 30, top: 10, right: 10, bottom: 20 }

const data = [

{ x: 30, y: 30, r: 30, title: 'I am the 1st circle!' },

{ x: 90, y: 30, r: 30, title: 'I am the 2nd circle!' },

{ x: 150, y: 30, r: 30, title: 'I am the 3rd circle!' },

{ x: 210, y: 30, r: 30, title: 'I am the 4th circle!' }

]

svg.selectAll('circle')

.data(data)

.enter()

.append('circle')

.attr('cx', d => d.x)

.attr('cy', d => d.y)

.attr('r', d => d.r)

.attr('fill', 'SteelBlue')

.on('click', function (d, i) {

mutable clicked = data[i].title

svg.selectAll('circle').attr('opacity', 1.0);

d3.select(this)

.attr('opacity', 0.5)

})

return svg.node()

}

/******************************************************************************

* END OF YOUR CODE *

******************************************************************************/

{

const height = 600

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 30, top: 10, right: 50, bottom: 20 }

const xScale = d3.scaleLinear()

.range([margin.left, width - margin.right])

.domain(d3.extent(pokemonBaseStats.map(d => d.x)))

const yScale = d3.scaleLinear()

.range([height - margin.bottom, margin.top])

.domain(d3.extent(pokemonBaseStats.map(d => d.y)))

// Setup the tooltip style, these are html and css, you can always lookup for their usage

// by searching the keywords

const tooltip = d3tip()

.style('border', 'solid 3px black')

.style('background-color', 'white')

.style('border-radius', '10px')

.style('float', 'left')

.style('font-family', 'monospace')

.html(d => `

Pokedex: ${d.pokedex_number} <br/>

Name: ${d.name} <br/>

Base Total: ${d.base_total} <br/>

Types: ${d.type1} ${d.type2}

</div>`)

// Apply tooltip to our SVG

svg.call(tooltip)

svg.selectAll('circle')

.data(pokemonBaseStats)

.enter()

.append('circle')

.attr('cx', d => xScale(d.x))

.attr('cy', d => yScale(d.y))

.attr('r', 5)

.attr('opacity', 0.5)

.attr('fill', d => d.is_legendary ? 'GoldenRod' : 'SteelBlue')

// When "mouseover" event triggers, show the tooltip

.on('mouseover', tooltip.show)

// Hide the tooltip when "mouseout"

.on('mouseout', tooltip.hide)

return svg.node()

}

// Dropdown menu contains the 10 songs in spotifySongs, with title and a default value

// "viewof" is a keyword in Observable notebook, it creates a binding between "trackName"

// and the underlying dropdown menu HTML input element

viewof trackName = select({

title: 'Pick a song:',

options: spotifySongs.map(song => song.trackName),

value: spotifySongs[0].trackName

})

{

const height = 400

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 70, top: 10, right: 30, bottom: 50 }

// Find the track information by "trackName", mostly we want the trackId

const song = _.find(spotifySongs, { trackName })

// Go through a chain of process with "spotifyDailyGlobalRanking" dataset

const data = _.chain(spotifyDailyGlobalRanking)

// Filter the dataset to only the data of selected track

.filter(d => d.trackId === song.trackId)

// Group data by month

.groupBy(d => d.date.substring(0, 7))

// Calculate the average of each month

.map((list, date) => ({ date, streams: _.sumBy(list, 'streams') / list.length }))

// Lodash keeps track of the chain with other information, .value() declares we are

// done with the process, and returns the end result, which in our case, is an array

// of the daily average streams of each month

.value()

const xScale = d3.scaleBand()

.padding(0.1)

.range([margin.left, width - margin.right])

.domain(_.range(1, 13).map(d => moment(`2017-${d}`).format('YYYY-MM')))

svg.append('g')

.call(d3.axisBottom(xScale))

.attr('transform', `translate(0,${height - margin.bottom})`)

const yScale = d3.scaleLinear()

.range([height - margin.bottom, margin.top])

// Use "maxDailyStreams" instead of calculating from the filtered data to keep the

// chart consistent across different songs

.domain([0, maxDailyStreams])

svg.append('g')

.call(d3.axisLeft(yScale).tickFormat(d3.format('.2s')))

.attr('transform', `translate(${margin.left},0)`)

// Make the column chart with "rect", its attributes can be found in the documentation:

// https://developer.mozilla.org/en-US/docs/Web/SVG/Element/rect

svg.selectAll('rect')

.data(data)

.enter()

.append('rect')

.attr('x', d => xScale(d.date))

.attr('y', d => yScale(d.streams))

.attr('height', d => yScale(0) - yScale(d.streams))

.attr('width', xScale.bandwidth())

.attr('fill', 'SteelBlue')

.append('title')

.text(d => `${d.date}: ${Math.round(d.streams)}`)

return svg.node()

}

// Update this variable using a click event

mutable selectedMonth = '2017-12'

/******************************************************************************

* TODO: *

* Try to add a click event to the column chart above, let the viewers to *

* select a month by clicking on the "rect"! *

* Hint: use .on('click', d => {}) to set the value of "selectedMonth" in the *

* format of "2017-12" *

******************************************************************************/

{

const height = 400

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 70, top: 10, right: 30, bottom: 50 }

// Find the track information by "trackName", mostly we want the trackId

const song = _.find(spotifySongs, { trackName })

// Go through a chain of process with "spotifyDailyGlobalRanking" dataset

const data = _.chain(spotifyDailyGlobalRanking)

// Filter the dataset to only the data of selected track

.filter(d => d.trackId === song.trackId)

// Group data by month

.groupBy(d => d.date.substring(0, 7))

// Calculate the average of each month

.map((list, date) => ({ date, streams: _.sumBy(list, 'streams') / list.length }))

// Lodash keeps track of the chain with other information, .value() declares we are

// done with the process, and returns the end result, which in our case, is an array

// of the daily average streams of each month

.value()

const xScale = d3.scaleBand()

.padding(0.1)

.range([margin.left, width - margin.right])

.domain(_.range(1, 13).map(d => moment(`2017-${d}`).format('YYYY-MM')))

svg.append('g')

.call(d3.axisBottom(xScale))

.attr('transform', `translate(0,${height - margin.bottom})`)

const yScale = d3.scaleLinear()

.range([height - margin.bottom, margin.top])

// Use "maxDailyStreams" instead of calculating from the filtered data to keep the

// chart consistent across different songs

.domain([0, maxDailyStreams])

svg.append('g')

.call(d3.axisLeft(yScale).tickFormat(d3.format('.2s')))

.attr('transform', `translate(${margin.left},0)`)

// Make the column chart with "rect", its attributes can be found in the documentation:

// https://developer.mozilla.org/en-US/docs/Web/SVG/Element/rect

svg.selectAll('rect')

.data(data)

.enter()

.append('rect')

.attr('x', d => xScale(d.date))

.attr('y', d => yScale(d.streams))

.attr('height', d => yScale(0) - yScale(d.streams))

.attr('width', xScale.bandwidth())

.attr('fill', 'SteelBlue')

.on('click', d => {

mutable selectedMonth = moment(d.date).format('YYYY-MM')

})

.append('title')

.text(d => `${d.date}: ${Math.round(d.streams)}`)

return svg.node()

}

/******************************************************************************

* END OF YOUR CODE *

******************************************************************************/

{

// Prepare the data

const song = _.find(spotifySongs, { trackName })

const data = spotifyDailyGlobalRanking

.filter(d => d.trackId === song.trackId && d.date.substring(0, 7) === selectedMonth)

// And then visualize

return vegaEmbed({

data: { values: data },

width: width - 200,

height: 400,

mark: 'bar',

encoding: {

x: {

field: 'date',

type: 'o',

timeUnit: 'date',

scale: {

// Instead of automatically inferring from data, we provide the range

// Otherwise, the missing data will not be shown as a missing bar

domain: _.range(1, moment(selectedMonth).daysInMonth() + 1)

}

},

// Adjust the axis label to 1 significant digit after decimal point

y: { field: 'streams', type: 'q', axis: { format: '.1s' } }

}

})

}

/******************************************************************************

* TODO: *

* Try to plot the column chart using D3 instead! *

* You don't need to make the exact same plot as Vega-Lite, just the *

* essential components will be good enough. *

******************************************************************************/

{

const height = 400

const svg = d3.select(DOM.svg(width, height))

const tooltip = d3tip()

.style('border', 'solid 1px black')

.style('background-color', 'white')

.style('border-radius', '10px')

.style('float', 'left')

.style('font-family', 'monospace')

.style('font-size', '12px')

.html(d => `

<div>

Date (date): ${moment(d.date).date()} <br/>

Streams: ${d.streams} <br/>

</div>`)

svg.call(tooltip)

const margin = { left: 70, top: 10, right: 30, bottom: 50 }

const song = _.find(spotifySongs, { trackName })

const data = spotifyDailyGlobalRanking

.filter(d => d.trackId === song.trackId && d.date.substring(0, 7) === selectedMonth)

const xScale = d3.scaleBand()

.padding(0.1)

.range([margin.left, width - margin.right])

.domain(_.range(1, moment(selectedMonth).daysInMonth() + 1))

svg.append('g')

.call(d3.axisBottom(xScale).tickFormat(d3.format('02d')))

.attr('transform', `translate(0,${height - margin.bottom})`)

const yScale = d3.scaleLinear()

.range([height - margin.bottom, margin.top])

.domain([0, d3.max(data.map(d => d.streams))])

svg.append('g')

.call(d3.axisLeft(yScale).tickFormat(d3.format('.2s')))

.attr('transform', `translate(${margin.left},0)`)

svg.append('text')

.attr('transform', `translate(${width/2},${height})`)

.style('text-anchor', 'middle')

.style('font-weight', 'bold')

.text('Date (date)')

svg.append('text')

.attr('transform', 'rotate(-90)')

.attr('y', 0)

.attr('x',0 - (height / 2))

.attr('dy', '1em')

.style('text-anchor', 'middle')

.style('font-weight', 'bold')

.text('Streams')

svg.selectAll('.bar')

.data(data)

.enter()

.append('rect')

.attr('x', d => xScale(moment(d.date).date()))

.attr('y', d => yScale(d.streams))

.attr('height', d => yScale(0) - yScale(d.streams))

.attr('width', xScale.bandwidth())

.attr('fill', 'SteelBlue')

.on('mouseover', tooltip.show)

.on('mousemove', tooltip.show)

.on('mouseout', tooltip.hide)

return svg.node()

}

/******************************************************************************

* END OF YOUR CODE *

******************************************************************************/

// Slider with integer values range from 0 to 364, each corresponding to a date in 2017

viewof dateIn2017Slider = slider({

title: 'Pick a date:',

value: 180,

min: 0,

max: moment([2017]).isLeapYear() ? 365 : 364,

step: 1,

display: v => moment([2017, 0, 1]).add(v, 'd').format('dddd, MMMM D YYYY')

})

{

const date = moment([2017, 0, 1]).add(dateIn2017Slider, 'd').format('YYYY-MM-DD')

const data = spotifyDailyGlobalRanking.filter(d => d.date === date)

.map(d => ({ ...d, trackName: _.find(spotifySongs, { trackId: d.trackId }).trackName }))

return vegaEmbed({

data: { values: data },

width: width - 200,

height: 400,

mark: 'bar',

encoding: {

x: {

field: 'trackName',

type: 'n',

// We provide the domain instead of auto-infer, to keep the plot consistent among changes

scale: { domain: spotifySongs.map(song => song.trackName) }

},

y: {

field: 'streams',

type: 'q',

axis: { format: '.1s' },

// Same reason as above to provide the domain

scale: { domain: [0, maxDailyStreams] }

}

})

}

// Choropleth plot (map regions encoded with colors)

{

// Prepare data

const song = _.find(spotifySongs, { trackName })

const date = moment([2017, 0, 1]).add(dateIn2017Slider2, 'd').format('YYYY-MM-DD')

const data = spotifyDailyRanking

// Filter out the selected song and selected date

.filter(d => d.trackId === song.trackId && d.date === date)

// Because we need to lookup the geographic information of the region, we need to find the

// cca3 code of the region using the countries dataset

.map(d => {

const country = countries[d.region.toUpperCase()]

return { ...d, cca3: country.cca3, country: country.name }

})

return vegaEmbed({

width: width - 200,

height: 400,

data: {

// Visualization with geographic data is not drawing data onto a map, instead,

// we draw the map while color encoding according to the data values

// This "worldTopoJson" dataset contains the borders of all the countries on Earth and

// we draw them out one by one, if there is a record in our data, we give that region a

// color according to the number of streams

values: worldTopoJson,

format: {

type: 'topojson',

feature: 'countries-land-10km'

}

},

// Vega-Lite transform, looking up values from our data, like a table join

transform: [{

lookup: 'properties.A3',

from: {

data: { values: data },

key: 'cca3',

fields: ['streams', 'country']

}

}],

// How do we project the latitude and longitude onto 2D screen

// See https://vega.github.io/vega/examples/world-map/ for more available projections

projection: {

type: 'equirectangular'

},

mark: 'geoshape',

encoding: {

// Color encode the number of streams in different regions

color: {

field: 'streams',

type: 'q',

scale: { scheme: 'blues', domain: [0, maxDailyRegionStream] }

},

// Provide a tooltip to show the details

tooltip: [

{field: 'streams', type: 'q'},

{field: 'country', type: 'n'}

]

}

})

}

// Variable holding the steps of the animation below

// Rerun this cell to see the animation below

mutable dateIn2017Mutable = 0

{

if (dateIn2017Mutable < 364) {

// Delay for 500 ms, yield is a keyword in Javascript, which is relayed to the concept

// of generator. It will take up a long passage (if not an article) to explain, just

// take it as a loop that keep updating the value of "dateIn2017Mutable" until 364

yield Promises.delay(500, dateIn2017Mutable)

// Then increment the variable

mutable dateIn2017Mutable++

} else {

// Do not increment if it is 31st December

yield dateIn2017Mutable

}

// Keep producing a new plot each half a second, we now have an animation of 2 frames per second

{

const date = moment([2017, 0, 1]).add(dateIn2017Mutable, 'd').format('YYYY-MM-DD')

const data = spotifyDailyGlobalRanking.filter(d => d.date === date)

.map(d => ({ ...d, trackName: _.find(spotifySongs, { trackId: d.trackId }).trackName }))

return vegaEmbed({

data: { values: data },

width: width - 200,

height: 400,

mark: 'bar',

encoding: {

x: {

field: 'trackName',

type: 'n',

scale: { domain: spotifySongs.map(song => song.trackName) }

},

y: {

field: 'streams',

type: 'q',

axis: { format: '.1s' },

scale: { domain: [0, maxDailyStreams] }

}

})

}

// Rerun this cell to see the animated transition

{

const height = 60

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 30, top: 10, right: 10, bottom: 20 }

const xScale = d3.scaleLinear()

.range([margin.left, width - margin.right])

.domain([0, 40])

svg.append('g')

.call(d3.axisBottom(xScale))

.attr('transform', `translate(0,${height - margin.bottom})`)

// Just append a circle, nothing special here yet!

svg.selectAll('circle')

.data([5])

.enter()

.append('circle')

.attr('cx', d => xScale(d))

.attr('cy', 20)

.attr('r', 10)

.attr('fill', 'SteelBlue')

// This is the update!

svg.selectAll('circle')

// Gives a new dataset, replacing 5 with 30

.data([30])

// Tell D3.js to make a transition

.transition()

// Update the visual representation, it can be any attributes, cx, cy, r, color, etc.

// And it must be placed after .transition()

.attr('cx', d => xScale(d))

// That last for 5000 ms

.duration(5000)

// With "d3.easeCubic" easing

.ease(d3.easeCubic)

return svg.node()

}

/******************************************************************************

* TODO: *

* Try other easing methods, duration and data value! e.g. d3.easeBounceOut! *

* A full list of easing methods can be found in the documentation: *

* https://github.com/d3/d3-ease *

*******************************************************************************/

{

const height = 60

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 30, top: 10, right: 10, bottom: 20 }

const xScale = d3.scaleLinear()

.range([margin.left, width - margin.right])

.domain([0, 40])

svg.append('g')

.call(d3.axisBottom(xScale))

.attr('transform', `translate(0,${height - margin.bottom})`)

svg.selectAll('circle')

.data([5])

.enter()

.append('circle')

.attr('cx', d => xScale(d))

.attr('cy', 20)

.attr('r', 10)

.attr('fill', 'SteelBlue')

svg.selectAll('circle')

.data([30])

.transition()

.attr('cx', d => xScale(d))

.duration(1500)

.ease(d3.easeBackOut)

return svg.node()

}

/******************************************************************************

* END OF YOUR CODE *

******************************************************************************/

{

const height = 300

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 30, top: 30, right: 30, bottom: 20 }

const xScale = d3.scaleLinear()

.range([margin.left, width - margin.right])

.domain([0, 10])

svg.append('g')

.call(d3.axisBottom(xScale))

.attr('transform', `translate(0,${height - margin.bottom})`)

const yScale = d3.scaleLinear()

.range([height - margin.bottom, margin.top])

.domain([0, 40])

svg.append('g')

.call(d3.axisLeft(yScale))

.attr('transform', `translate(${margin.left},0)`)

const colorScale = d3.scaleOrdinal(d3.schemeSet3)

.domain([0, 10])

let circles = svg.selectAll('circle')

let data = []

while (true) {

// No effect to this plot, just to print the values in the cell above

mutable dataArray = data

yield svg.node()

// Update data

const update = circles

.data(data)

// Remove SVG elements associated with the deleted data points

update.exit().remove()

// Add SVG elements for the newly added data points

circles = update.enter()

.append('circle')

.attr('cx', (d, i) => xScale(i + 1))

.attr('r', 20)

.attr('fill', (d, i) => colorScale(i))

// We want the variable "circles" to hold not just the set of newly added

// data points, but all the exisiting data points

// .merge is the function to combine two sets

.merge(circles)

// If nothing to animate, don't wait

if (data.length !== 0) {

// Wait until the transition animation is finished

await circles

.transition()

.attr('cy', d => yScale(d))

.ease(d3.easeBounceOut)

.duration(1000)

// calling .end() is important, it returns a "waitable" object for "await" to

// wait for. It is a concept call "Promise", similar to the concept of generator,

// it will take a long passage to explain, just take it as a sandglass to wait for

.end()

}

if (data.length >= 1)

data[data.length - 1] = 0

if (data.length <= 10)

data.push(40)

if (data.length > 10 && data[data.length - 1] === 0)

data = []

}

// Rerun this cell to see the animation

{

const height = 400

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 70, top: 10, right: 30, bottom: 50 }

// A function to retrieve the data of the specified date

// It always returns an array with all 10 songs

const rankingOnDate = (date) => {

const dateString = moment(date).format('YYYY-MM-DD')

const data = spotifyDailyGlobalRanking.filter(d => d.date === dateString)

return spotifySongs.map(song => {

const ranking = _.find(data, { trackId: song.trackId })

return ranking || { trackId: song.trackId, streams: 0 }

})

}

const xScale = d3.scaleBand()

.padding(0.1)

.range([margin.left, width - margin.right])

.domain(spotifySongs.map(song => song.trackId))

svg.append('g')

.call(d3.axisBottom(xScale)

.tickFormat(v => _.find(spotifySongs, { trackId: v }).trackName.substr(0, 15)))

.attr('transform', `translate(0,${height - margin.bottom})`)

const yScale = d3.scaleLinear()

.range([height - margin.bottom, margin.top])

.domain([0, maxDailyStreams])

svg.append('g')

.call(d3.axisLeft(yScale).tickFormat(d3.format('.2s')))

.attr('transform', `translate(${margin.left},0)`)

// Make the text at the top right corner

const dateText = svg.append('text')

.text(`Spotify Streams on ${moment([2017, 0, 1]).format('YYYY-MM-DD')}`)

.attr('transform', `translate(${width - 300}, 20)`)

const bars = svg.selectAll('rect')

.data(rankingOnDate('2017-01-01'))

.enter()

.append('rect')

.attr('x', d => xScale(d.trackId))

.attr('y', d => yScale(d.streams))

.attr('height', d => yScale(0) - yScale(d.streams))

.attr('width', xScale.bandwidth())

.attr('fill', 'SteelBlue')

let date = moment([2017, 0, 1])

while (true) {

yield svg.node();

// Increment by 1 day

date = date.add(1, 'd')

// Stop if it is 31st December, reminded that month starts counting from 0

if (date.isAfter([2017, 11, 31])) break

// Update the text at the top right corner

dateText.text(`Spotify Streams on ${date.format('YYYY-MM-DD')}`)

await bars

// Because the "rankingOnDate" always return all 10 songs, so that we only

// need to focus on updating the values and transitions, no .enter(), .exit()

// or .merge() is needed

.data(rankingOnDate(date))

.transition()

.duration(500)

.ease(d3.easeCubic)

.attr('y', d => yScale(d.streams))

.attr('height', d => yScale(0) - yScale(d.streams))

.end()

}

// Rerun this cell to see the animation

{

const height = 600

const svg = d3.select(DOM.svg(width, height))

const margin = { left: 30, top: 10, right: 50, bottom: 20 }

const xScale = d3.scaleLinear()

.range([margin.left, width - margin.right])

.domain(d3.extent(pokemonBaseStats.map(d => d.x)))

const yScale = d3.scaleLinear()

.range([height - margin.bottom, margin.top])

.domain(d3.extent(pokemonBaseStats.map(d => d.y)))

const tooltip = d3tip()

.style('border', 'solid 3px black')

.style('background-color', 'white')

.style('border-radius', '10px')

.style('float', 'left')

.style('font-family', 'monospace')

.html(d => `

Pokedex: ${d.pokedex_number} <br/>

Name: ${d.name} <br/>

Base Total: ${d.base_total} <br/>

Types: ${d.type1} ${d.type2}

</div>`)

svg.call(tooltip)

let circles = svg.selectAll('circle')

let data = []

while(true) {

yield svg.node()

const update = circles

.data(data)

update.exit().remove()

circles = update.enter()

.append('circle')

.attr('cx', d => xScale(d.x))

.attr('cy', d => yScale(d.y))

.attr('r', 0)

.attr('opacity', 0.5)

.attr('fill', d => d.is_legendary ? 'GoldenRod' : 'SteelBlue')

.on('mouseover', tooltip.show)

.on('mouseout', tooltip.hide)

.merge(circles)

if (data.length !== 0) {

await circles

.transition()

.attr('r', 10)

.ease(d3.easeElasticOut)

.duration(1000)

.end()

}

if (data.length < pokemonBaseStats.length) {

data.push(pokemonBaseStats[data.length])

} else {

break

}

Purpose-built for displays of data