Modularity

D3 v3 was one large library. You had to include all of it, even if you didn't need all of it.

Modularity

D3 v3 was one large library. You had to include all of it, even if you didn't need all of it.

D3 v4 is actually a set of small modules. You can choose to use one or more as you need them.

https://github.com/d3/

Modularity

For example: https://github.com/d3/d3-scale Can be installed via npm:

npm install d3-scale

Modularity

For example: https://github.com/d3/d3-scale Can be installed via npm:

npm install d3-scale

Note that each module has it's own dependencies. When installing them via npm, they will be pulled down for you, but if you were to include them manually, you need to make sure those are included as well. For example:

<script src="https://d3js.org/d3-array.v1.min.js"></script>
<script src="https://d3js.org/d3-collection.v1.min.js"></script>
<script src="https://d3js.org/d3-color.v1.min.js"></script>
<script src="https://d3js.org/d3-format.v1.min.js"></script>
<script src="https://d3js.org/d3-interpolate.v1.min.js"></script>
<script src="https://d3js.org/d3-time.v1.min.js"></script>
<script src="https://d3js.org/d3-time-format.v2.min.js"></script>
<script src="https://d3js.org/d3-scale.v1.min.js"></script>

Most likely you will use some sort of build system to package your JS. Mike Bostock has suggested using Rollup an example of which you can find here.

Modularity

You can still use the entire v4 build by including it using your favorite method:

<script src="https://d3js.org/d3.v4.js"></script>

Namespacing

D3 v3's API was logically namespaced. For example:

• d3.scale.linear
• d3.scale.ordinal
• d3.time.format
• d3.svg.axis

Namespacing

D3 v3's API was logically namespaced. For example:

• d3.scale.linear
• d3.scale.ordinal
• d3.time.format
• d3.svg.axis

In D3 v4, all modules share a flat namespace d3.* as a result of adopting ES6 modules.

• d3.scale.linear is now d3.scaleLinear
• d3.layout.treemap is now d3.treemap

Namespacing

D3 v3's API was logically namespaced. For example:

• d3.scale.linear
• d3.scale.ordinal
• d3.time.format
• d3.svg.axis

In D3 v4, all modules share a flat namespace d3.* as a result of adopting ES6 modules.

• d3.scale.linear is now d3.scaleLinear
• d3.layout.treemap is now d3.treemap

This does mean you can't just swap in D3 v4 and expect it to work.

Method accessors

Many utility methods now take an accessor method that has a consistent signature:

function(d, i, data) {...}

For example:

var settlersData = [
  {name: "Wood", count: 2},
  {name: "Ore", count: 3},
  {name: "Sheep", count: 4},
  {name: "Wheat", count: 1}
];
d3.min(settlersData, function(d, i, data) {
  return d.count;
});

Previously some methods were not consistent about this (for example, d3.quantile).

Canvas Rendering

In v3, d3's few actual rendering methods only rendered to SVG. Starting v4, many of the rendering helpers now have a new context method that lets you pass in a Canvas context to render to.

For example:

var line = d3.line()
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.value); });

Canvas Rendering

In v3, d3's few actual rendering methods only rendered to SVG. Starting v4, many of the rendering helpers now have a new context method that lets you pass in a Canvas context to render to.

For example:

var line = d3.line()
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.value); });

To render SVG:

path.datum(data).attr("d", line);

Canvas Rendering

In v3, d3's few actual rendering methods only rendered to SVG. Starting v4, many of the rendering helpers now have a new context method that lets you pass in a Canvas context to render to.

For example:

var line = d3.line()
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.value); });

To render SVG:

path.datum(data).attr("d", line);

To render to Canvas:

line.context(context)(data);

You can see more examples in the shapes module: d3-shape.

Selections

• Selections no longer subclass Array by extending its prototype. They are now plain objects.

Selections

• Selections no longer subclass Array by extending its prototype. They are now plain objects.

• There is a new method called .nodes to retrieve all nodes within a selection as an array.

Selections

• Selections no longer subclass Array by extending its prototype. They are now plain objects.

• There is a new method called .nodes to retrieve all nodes within a selection as an array.

• Selections are immutable (parents and elements never change, though their attributes do.) For example. selection.sort will return a new selection.

Selections

• selection.append now inserts elements in the order of the data bound, instead of at the end:

For example, in v3:

d3.select("body").selectAll("span").data([1, 3, 5], String).enter().append("span").text(String);
d3.select("body").selectAll("span").data([1, 2, 3, 4, 5], String).enter().append("span").text(String);
// 13524

In v4:

d3.select("body").selectAll("span").data([1, 3, 5], String).enter().append("span").text(String);
d3.select("body").selectAll("span").data([1, 2, 3, 4, 5], String).enter().append("span").text(String);
// 12345

Selections

• selection.append now inserts elements in the order of the data bound, instead of at the end:

For example, in v3:

d3.select("body").selectAll("span").data([1, 3, 5], String).enter().append("span").text(String);
d3.select("body").selectAll("span").data([1, 2, 3, 4, 5], String).enter().append("span").text(String);
// 13524

In v4:

d3.select("body").selectAll("span").data([1, 3, 5], String).enter().append("span").text(String);
d3.select("body").selectAll("span").data([1, 2, 3, 4, 5], String).enter().append("span").text(String);
// 12345

• New lifecycle event (ish)! merge.

example

In v3:

var circleBinding = svg.selectAll("circle").data(data);
circleBinding.style("fill", "blue"); // UPDATE
circleBinding.exit().remove(); // EXIT
circleBinding.enter().append("circle") // ENTER; modifies UPDATE!
    .style("fill", "green");
circleBinding // ENTER + UPDATE
    .style("stroke", "black");

example

In v3:

var circleBinding = svg.selectAll("circle").data(data);
circleBinding.style("fill", "blue"); // UPDATE
circleBinding.exit().remove(); // EXIT
circleBinding.enter().append("circle") // ENTER; modifies UPDATE!
    .style("fill", "green");
circleBinding // ENTER + UPDATE
    .style("stroke", "black");

In v4:

var circleBinding = svg.selectAll("circle").data(data); 
circleBinding.style("fill", "blue"); // UPDATE
circleBinding.exit().remove(); // EXIT
circleBinding.enter().append("circle") // ENTER
    .style("fill", "green")
  .merge(circleBinding) // ENTER + UPDATE
    .style("stroke", "black");

Selections (d3-selection)

• To move a selection to the front of its siblings call selection.raise. To move it backwards, call selection.lower

Selections (d3-selection)

• To move a selection to the front of its siblings call selection.raise. To move it backwards, call selection.lower

• You can dispatch events on selections using selection.dispatch

Selections (d3-selection)

• To move a selection to the front of its siblings call selection.raise. To move it backwards, call selection.lower

• You can dispatch events on selections using selection.dispatch

• The selection.call method no longer sets this to be the selection. It is now passed as the first argument to the callback.

In v3:

d3.selectAll("div.states")
  .call(function() {
    this.style('color', 'red');
  })

In V4:

d3.selectAll("div.states")
  .call(function(statesSelection) {
    statesSelection.style('color', 'red');
  })

Multi-Selections (d3-selection-multi)

In d3 v3, you could easily set multiple style or attribute properties like this:

d3.select("h4").style({
  color: "red", background: "yellow"
});

Multi-Selections (d3-selection-multi)

In d3 v3, you could easily set multiple style or attribute properties like this:

d3.select("h4").style({
  color: "red", background: "yellow"
});

In v4, you can no longer do that. Even this does not work:

d3.select("h4").style({ color: "red" });

Instead, you have to set the key and value explicitly:

d3.select("h4").style("color", "red");

Multi-Selections (d3-selection-multi)

Multi-selections allows you to set multiple properties with one call, but it is not included by default with the standard build. You have to include it yourself:

<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/d3-selection-multi.v0.4.min.js"></script>

This will let you:

var div = d3.selectAll("div")
    .attrs({ "title": "Hello, world!", "name" : "greeter" })
    .styles({ "color": "red", "background" : "green" });

Note that it's styles and attrs, not style and attr as before.

Transitions (d3-transition)

You can create transitions and then share them across selections

var t = d3.transition()
    .duration(750)
    .ease(d3.easeLinear);
d3.selectAll(".apple").transition(t)
    .style("fill", "red");
d3.selectAll(".orange").transition(t)
    .style("fill", "orange");

Transitions (d3-transition)

Delays are now relative to previous transition, not the first transition

d3.selectAll(".apple")
  .transition() // First fade to green.
    .style("fill", "green")
  .transition() // Then red.
    .style("fill", "red")
  .transition() // Wait one second. Then brown, and remove.
    .delay(1000)
    .style("fill", "brown")
    .remove();

Transitions (d3-transition)

Delays are now relative to previous transition, not the first transition

d3.selectAll(".apple")
  .transition() // First fade to green.
    .style("fill", "green")
  .transition() // Then red.
    .style("fill", "red")
  .transition() // Wait one second. Then brown, and remove.
    .delay(1000)
    .style("fill", "brown")
    .remove();

• selection.interrupt stops active transitions and cancels all scheduled transitions on the selection.

Transitions (d3-transition)

Delays are now relative to previous transition, not the first transition

d3.selectAll(".apple")
  .transition() // First fade to green.
    .style("fill", "green")
  .transition() // Then red.
    .style("fill", "red")
  .transition() // Wait one second. Then brown, and remove.
    .delay(1000)
    .style("fill", "brown")
    .remove();

• selection.interrupt stops active transitions and cancels all scheduled transitions on the selection.

• All transition callbacks recieve the standard arguments (d, i, nodes) - which impacts in particular the attrTween and styleTween functions which took a tween function or style value as the third argument.

• d3.active lets you select a transition that is currently active on a given node.

Example

var whiteblue = d3.interpolateRgb("#eee", "steelblue"),
    blueorange = d3.interpolateRgb("steelblue", "orange"),
    orangewhite = d3.interpolateRgb("orange", "#eee");
d3.select("body").selectAll("div")
    .data(d3.range(n))
  .enter().append("div")
  .transition()
    .delay(function(d, i) { return i + Math.random() * n / 4; })
    .ease(d3.easeLinear)
    .on("start", function repeat() {
        d3.active(this)
            .styleTween("background-color", function() { return whiteblue; })
          .transition()
            .delay(1000)
            .styleTween("background-color", function() { return blueorange; })
          .transition()
            .delay(1000)
            .styleTween("background-color", function() { return orangewhite; })
          .transition()
            .delay(n)
            .on("start", repeat);
      });

Scales (d3-scale)

• Lots of renaming:

  • d3.scale.linear → d3.scaleLinear
  • d3.scale.sqrt → d3.scaleSqrt
  • d3.scale.pow → d3.scalePow

Scales (d3-scale)

• Lots of renaming:

  • d3.scale.linear → d3.scaleLinear
  • d3.scale.sqrt → d3.scaleSqrt
  • d3.scale.pow → d3.scalePow

• Scales now generate ticks in the same order as the domain (useful if you have a descending scale)

Scales (d3-scale)

• Lots of renaming:

  • d3.scale.linear → d3.scaleLinear
  • d3.scale.sqrt → d3.scaleSqrt
  • d3.scale.pow → d3.scalePow

• Scales now generate ticks in the same order as the domain (useful if you have a descending scale)

• You can specify what to do when a scale recieves a value that is outside the domain using .unknown:

var x = d3.scaleOrdinal()
    .domain([0, 1])
    .range(["red", "blue"])
    .unknown(undefined);
x(0) // "red"
x(2); // undefined

Scales (d3-scale)

• Categorical color scales have changed. They have been renamed: d3.scale.category10 → d3.schemeCategory10 and they are no longer actual scales but just array of numbers:

In v3:

var color = d3.scale.category10();

In V4:

var color = d3.scaleOrdinal(d3.schemeCategory10);

Scales (d3-scale)

• Categorical color scales have changed. They have been renamed: d3.scale.category10 → d3.schemeCategory10 and they are no longer actual scales but just array of numbers:

In v3:

var color = d3.scale.category10();

In V4:

var color = d3.scaleOrdinal(d3.schemeCategory10);

• New sequential scales - instead of outputting to a range, they use an interpolator. Most useful for sequential color schemes. Lots of new interplators inspired by matplotlib's perceptually motivated colormaps.

z = d3.scaleSequential(d3.interpolateViridis);

Histograms (d3-array)

d3.histogram

In v4:

var values = [
  { val : 1 }, { val : 1 }, { val : 4 }, { val : 5 }, { val : 23 }, 
  { val : 1 }, { val : 4 }
];
var hist = d3.histogram()
  .thresholds(3)
  .value(function(d) { 
    return d.val; 
  });

Histograms (d3-array)

d3.histogram

• d3.layouts.histogram is now d3.histogram

Histograms (d3-array)

d3.histogram

• d3.layouts.histogram is now d3.histogram

• The bins method was renamed to thresholds

Histograms (d3-array)

d3.histogram

• d3.layouts.histogram is now d3.histogram

• The bins method was renamed to thresholds

• dx which specified the bin width is gone, there are now x0 and x1 which specify the start and end range of a bin. x0 will equal the x1 of the previous bin.

Histograms (d3-array)

d3.histogram

• d3.layouts.histogram is now d3.histogram

• The bins method was renamed to thresholds

• dx which specified the bin width is gone, there are now x0 and x1 which specify the start and end range of a bin. x0 will equal the x1 of the previous bin.

The binning is also now different. In v3 the values we have for x and dx are:

[1, 7.33333] [8.33333333, 7.33333], [15.666666666666666, 7.33333]

In V4 the bins are:

[1, 10] [10, 20] [20, 23]

Axes (d3-axis)

In v3, you had to style the axes or it would look like this:

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}
.axis text {
  font: 10px sans-serif;
}

d3.select(".axis")
    .call(d3.svg.axis()
        .scale(x)
        .orient("bottom"));

Axes (d3-axis)

In v4, styling is taken care of:

var x = d3.scaleLinear()
  .domain([1,10])
  .range([1,300]);
var axis = d3.axisTop(x);
d3.select("body").append("svg")
    .attr("class", "axis")
    .attr("width", 310)
    .attr("height", 30)
  .append("g")
    .attr("transform", "translate(0,20)")
    .call(axis);

Results in:

The default styles have been changed to offset the axis by 0.5px which fixes a crisp-edges rendering issue on safari where the axis would be drawn 2px thick.

Axes (d3-axis)

• Note that instead of setting the axis orientation we now use
  • axisLeft
  • axisRight
  • axisTop
  • axisBottom

Axes (d3-axis)

• Note that instead of setting the axis orientation we now use
  • axisLeft
  • axisRight
  • axisTop
  • axisBottom

axis.tickArguments([20, "s"]) - shorthand for calling axis.ticks(20) and axis.tickFormat(d3.format("s")).

Collections (d3-collections)

Aggregates all functions having to do with data structures

• Objects
• Maps
• Sets
• Nests

Collections (d3-collections)

d3.set

• Renamed: set.forEach to set.each
• Now accepts an accessor function

var values = [
  { val : 1 },
    { val : 1 },
    { val : 4 },
    { val : 5 },
    { val : 23 },
    { val : 1 },
    { val : 4 }
];
var x  = d3.set(values, function(d) { 
  return d.val; 
}); // [1,4,5,23]

Collections (d3-collections)

d3.map

• Renamed: map.forEach → map.each.
• Argument order changed for each callback to (value, key, map):

var values = [
  { val : 1, name: "One"},
    { val : 1, name: "One" },
    { val : 4, name: "Four" },
    { val : 5, name: "Five" },
    { val : 23, name: "TwentyThree" },
    { val : 1, name: "One" }
];
var x  = d3.map(values, function(d) { return d.name; });
x.each(function(val, key, map) {
  console.log(val);
}); // { val : 1, name: "One"},  { val : 4, name: "Four" }, { val : 5, name: "Five" },...

In V3, the order was (key, value). So if you would get: ["One", "Four", "Five", "TwentyThree"] if you forget to reverse your callback variables...

Collections (d3-collections)

Both d3.set and d3.map

• Return the collection, when you call .add to add a new element, instead of the added value.
• Have new .clear methods to clear the collections.

Arrays (d3-array)

d3.scan(arr, fn)

D3 v3's d3.min and d3.max would return the min or max element appropriately, but you couldn't easily find out the original position of that element. In v4, d3.scan does just that using a comparator function.

var settlersData = [
  {name: "Wood", count: 2},
  {name: "Ore", count: 3},
  {name: "Sheep", count: 4},
  {name: "Wheat", count: 1}
];
var idx = d3.scan(settlersData, function(a, b) { 
  return a.count - b.count; 
}); // 3
settlersData[idx]; // {name: "Wheat", count: 1}

Arrays (d3-array)

d3.ticks(start, end, count)

A new method that will generate an array of count+1 items equally spaced between start and end.

var ticks = d3.ticks(0, 10, 5); // [0, 2, 4, 6, 8, 10]

Note that this method has nothing to do with axes.

d3.tickStep(start, end, count)

Will give you the space between values that you would obtain from d3.ticks:

d3.tickStep(0,10,5);
// 2

Arrays (d3-array)

d3.range(start, end, increment)

Floating point math is fun:

0.2 * 3 = 0.6000000000000001

In D3 v3, d3.range tried to handle this:

d3.range(0, 1, 0.2) // [0, 0.2, 0.4, 0.6, 0.8]

D3 v4's d3.range no longer does that:

d3.range(0, 1, 0.2) // [0, 0.2, 0.4, 0.6000000000000001, 0.8]

This only matters if you are dealing with floating point numbers and you can always use d3.format to present them more consistently.

Colors (d3-color)

• All colors now have an opacity method exposed: .opacity which takes a value from 0 to 1.

Colors (d3-color)

• All colors now have an opacity method exposed: .opacity which takes a value from 0 to 1.

• You can also pass an optional opacity argument to d3.rgb, d3.hsl, d3.lab, d3.hcl or d3.cubehelix.

Colors (d3-color)

• All colors now have an opacity method exposed: .opacity which takes a value from 0 to 1.

• You can also pass an optional opacity argument to d3.rgb, d3.hsl, d3.lab, d3.hcl or d3.cubehelix.

• You can now parse CSS color specifiers with d3.color:

var red = d3.color("hsl(0, 80%, 50%)"); 
// {h: 0, l: 0.5, s: 0.8, opacity: 1}

Colors (d3-color)

• All colors now have an opacity method exposed: .opacity which takes a value from 0 to 1.

• You can also pass an optional opacity argument to d3.rgb, d3.hsl, d3.lab, d3.hcl or d3.cubehelix.

• You can now parse CSS color specifiers with d3.color:

var red = d3.color("hsl(0, 80%, 50%)"); 
// {h: 0, l: 0.5, s: 0.8, opacity: 1}

• The toString method will now return an rgb or rgba string in the form of rgb(12,13,42).

Colors (d3-color)

• All colors now have an opacity method exposed: .opacity which takes a value from 0 to 1.

• You can also pass an optional opacity argument to d3.rgb, d3.hsl, d3.lab, d3.hcl or d3.cubehelix.

• You can now parse CSS color specifiers with d3.color:

var red = d3.color("hsl(0, 80%, 50%)"); 
// {h: 0, l: 0.5, s: 0.8, opacity: 1}

• The toString method will now return an rgb or rgba string in the form of rgb(12,13,42).

• There is no more .hsl method on a color instance. To convert a color to hsl call the d3.hsl helper method:

d3.hsl(red) 
// Color instance: {h: 0, s: 0.8, l: 0.5, opacity: 1}

Colors (d3-color)

• All colors now have an opacity method exposed: .opacity which takes a value from 0 to 1.

• You can also pass an optional opacity argument to d3.rgb, d3.hsl, d3.lab, d3.hcl or d3.cubehelix.

• You can now parse CSS color specifiers with d3.color:

var red = d3.color("hsl(0, 80%, 50%)"); 
// {h: 0, l: 0.5, s: 0.8, opacity: 1}

• The toString method will now return an rgb or rgba string in the form of rgb(12,13,42).

• There is no more .hsl method on a color instance. To convert a color to hsl call the d3.hsl helper method:

d3.hsl(red) 
// Color instance: {h: 0, s: 0.8, l: 0.5, opacity: 1}

• New method called color.displayable() will return false if the color is out of gamut.

Easing (d3-ease)

In v3, you used easing function string names to specify the ones you wanted like "linear" or "cubic-in-out". In V4, we use methods instead:

Instead of:

var e = d3.ease("elastic-out-in", 1.2);

Use:

var e = d3.easeElastic.amplitude(1.2);

Visual reference for the functions

Animated version

Dispatching (d3-dispatch)

• Instead of exposing individual methods for each event type, you just use call to fire off an event (note these are different from the selection.call).

In V3:

dispatcher.foo.call(that, "Hello, Foo!");

In V4:

dispatcher.call("foo", that, "Hello, Foo!");

Dispatching (d3-dispatch)

• Instead of exposing individual methods for each event type, you just use call to fire off an event (note these are different from the selection.call).

In V3:

dispatcher.foo.call(that, "Hello, Foo!");

In V4:

dispatcher.call("foo", that, "Hello, Foo!");

• The on method accepts multiple event names, separated by a space:

dispatcher.on("foo bar", function(message) {
  console.log(message);
});

Brushing (d3-brush)

• d3.svg.brush is now d3.brush

Brushing (d3-brush)

• d3.svg.brush is now d3.brush

• There are now 3 classes for brushing along the x, y or both dimensions: d3.brushX, d3.brushY or d3.brush.

Brushing (d3-brush)

• d3.svg.brush is now d3.brush

• There are now 3 classes for brushing along the x, y or both dimensions: d3.brushX, d3.brushY or d3.brush.

• Brush is no longer depending on scales - they define a selection in screen coordinates and you can invert it using a scale of choice.

Brushing (d3-brush)

• d3.svg.brush is now d3.brush

• There are now 3 classes for brushing along the x, y or both dimensions: d3.brushX, d3.brushY or d3.brush.

• Brush is no longer depending on scales - they define a selection in screen coordinates and you can invert it using a scale of choice.

• You can restrict a brushing area to a brush.extent, otherwise it defaults to the full SVG element.

Brushing (d3-brush)

• d3.svg.brush is now d3.brush

• There are now 3 classes for brushing along the x, y or both dimensions: d3.brushX, d3.brushY or d3.brush.

• Brush is no longer depending on scales - they define a selection in screen coordinates and you can invert it using a scale of choice.

• You can restrict a brushing area to a brush.extent, otherwise it defaults to the full SVG element.

• A brush doesn't store the active selection - it is now stored on the element to which the brush was applied. You can access it either via:

  • a brush event - retrieve element by calling event.selection.
  • Call d3.brushSelection on any given element.

Brushing (d3-brush)

• d3.svg.brush is now d3.brush

• There are now 3 classes for brushing along the x, y or both dimensions: d3.brushX, d3.brushY or d3.brush.

• Brush is no longer depending on scales - they define a selection in screen coordinates and you can invert it using a scale of choice.

• You can restrict a brushing area to a brush.extent, otherwise it defaults to the full SVG element.

• A brush doesn't store the active selection - it is now stored on the element to which the brush was applied. You can access it either via:

  • a brush event - retrieve element by calling event.selection.
  • Call d3.brushSelection on any given element.

• You can move the brush by calling brush.move

Brushing (d3-brush)

• d3.svg.brush is now d3.brush

• There are now 3 classes for brushing along the x, y or both dimensions: d3.brushX, d3.brushY or d3.brush.

• Brush is no longer depending on scales - they define a selection in screen coordinates and you can invert it using a scale of choice.

• You can restrict a brushing area to a brush.extent, otherwise it defaults to the full SVG element.

• A brush doesn't store the active selection - it is now stored on the element to which the brush was applied. You can access it either via:

  • a brush event - retrieve element by calling event.selection.
  • Call d3.brushSelection on any given element.

• You can move the brush by calling brush.move

• There are now default styling applied, so you don't have to add them manually.

Brushing (d3-brush)

d3.brush

var brush = d3.brush()
    .on("start brush", brushed)
    .on("end", brushended);
function brushed() {
  var s = d3.event.selection;
  //...
}
function brushended() {
  if (!d3.event.selection) {
    //...
  }
}
svg.append("g")
  .attr("class", "brush")
  .call(brush)
  .call(brush.move, [[307, 167], [611, 539]]);

Example: http://bl.ocks.org/mbostock/0d20834e3d5a46138752f86b9b79727e

Dragging (d3-drag)

• d3.behavior.drag → d3.drag

• There's a new method called subject which lets you define an accessor to return what is being dragged. This is useful when using canvas, since there are no DOM nodes representing the content. The result of this accessor function call will be available on a drag event under d3.event.subject. Example: http://bl.ocks.org/mbostock/444757cc9f0fde320a5f469cd36860f4

Dragging (d3-drag)

• d3.behavior.drag → d3.drag

• There's a new method called subject which lets you define an accessor to return what is being dragged. This is useful when using canvas, since there are no DOM nodes representing the content. The result of this accessor function call will be available on a drag event under d3.event.subject. Example: http://bl.ocks.org/mbostock/444757cc9f0fde320a5f469cd36860f4

• There is now an on method to bind to start, end and drag events:

canvas.call(d3.drag()
    .subject(dragsubject)
    .on("start", dragstarted)
    .on("drag", dragged)
    .on("end", dragended)
    .on("start.render drag.render end.render", render));

Dragging (d3-drag)

• d3.behavior.drag → d3.drag

• There's a new method called subject which lets you define an accessor to return what is being dragged. This is useful when using canvas, since there are no DOM nodes representing the content. The result of this accessor function call will be available on a drag event under d3.event.subject. Example: http://bl.ocks.org/mbostock/444757cc9f0fde320a5f469cd36860f4

• There is now an on method to bind to start, end and drag events:

canvas.call(d3.drag()
    .subject(dragsubject)
    .on("start", dragstarted)
    .on("drag", dragged)
    .on("end", dragended)
    .on("start.render drag.render end.render", render));

• There are also d3.dragEnable and d3.dragDisable methods to control dragging support at a higher level.

Force layout (d3-force)

• Renamed: d3.layout.force → d3.forceSimulation.

Force layout (d3-force)

• Renamed: d3.layout.force → d3.forceSimulation.

• The force algorithm changed to track node velocity (node.vx and node.vy) and position (node.x and node.y, not just position (formally node.px and node.py).

Force layout (d3-force)

• Renamed: d3.layout.force → d3.forceSimulation.

• The force algorithm changed to track node velocity (node.vx and node.vy) and position (node.x and node.y, not just position (formally node.px and node.py).

• Initial node position is now deterministic

Force layout (d3-force)

• Renamed: d3.layout.force → d3.forceSimulation.

• The force algorithm changed to track node velocity (node.vx and node.vy) and position (node.x and node.y, not just position (formally node.px and node.py).

• Initial node position is now deterministic

• If you need to find the closest node to a pointer, you no longer have to use a Voronoi SVG overlay, you can call simulation.find.

Force layout (d3-force)

• Renamed: d3.layout.force → d3.forceSimulation.

• The force algorithm changed to track node velocity (node.vx and node.vy) and position (node.x and node.y, not just position (formally node.px and node.py).

• Initial node position is now deterministic

• If you need to find the closest node to a pointer, you no longer have to use a Voronoi SVG overlay, you can call simulation.find.

• Old v3 version of Les Miserables. In v4: Les Miserables with dragging

var simulation = d3.forceSimulation()
  .force("link", d3.forceLink().id(function(d) { return d.id; }))
  .force("charge", d3.forceManyBody())
  .force("center", d3.forceCenter(width / 2, height / 2));
simulation
  .nodes(graph.nodes)
  .on("tick", ticked);
simulation.force("link")
  .links(graph.links);

Hierarchies (d3-hierarchy)

• Lots of renaming:

  • d3.layout.cluster → d3.cluster
  • d3.layout.hierarchy → d3.hierarchy

• New useful method d3.stratify to convert flat arrays of objects into the hierarchical structures required by hierarchical layouts:

[
  {"name": "Eve",   "parent": ""},
  {"name": "Cain",  "parent": "Eve"},
  {"name": "Seth",  "parent": "Eve"},
  {"name": "Enos",  "parent": "Seth"}
]

To convert to a hierarchy:

var root = d3.stratify()
    .id(function(d) { return d.name; })
    .parentId(function(d) { return d.parent; })
    (table);

Hierarchies (d3-hierarchy)

• All hierarchical layouts now expect a hierarchy object. So if you already have json in the right form you first have to call var struct = d3.hierarchy(myJsonObj) to convert it and then pass it to your layout.

Hierarchies (d3-hierarchy)

• All hierarchical layouts now expect a hierarchy object. So if you already have json in the right form you first have to call var struct = d3.hierarchy(myJsonObj) to convert it and then pass it to your layout.

• There are new methods for aggregating special nodes like:

  • nodes.leaves to get just leaf nodes
  • nodes.descendents
  • nodes.anscestors
  • To get the links in the form of {source, target} call nodes.links (which you used to obtain from your layouts.)

Queue (d3-queue)

• A queue evaluates zero or more deferred asynchronous tasks with configurable concurrency
• Used to be a separate library, now included in the default bundle as d3.queue.

d3.queue()
  .defer(d3.json, 'states.json')
  .defer(d3.json, 'cities.json')
  .await(function(error, states, cities) {
    // make map
  });
// or:
d3.queue()
  .defer(d3.json, 'states.json')
  .defer(d3.json, 'cities.json')
  .awaitAll(function(error, results) {
    // results is an array of the returned objects.
  });

Delimiter-Separated Values (d3-dsv)

• Lots of renaming:

  • d3.csv.parse → d3.csvParse
  • d3.csv.parseRows → d3.csvParseRows

Delimiter-Separated Values (d3-dsv)

• Lots of renaming:

  • d3.csv.parse → d3.csvParse
  • d3.csv.parseRows → d3.csvParseRows

• The original d3.csv and d3.tsv for loading files have not been renamed.

Delimiter-Separated Values (d3-dsv)

• Lots of renaming:

  • d3.csv.parse → d3.csvParse
  • d3.csv.parseRows → d3.csvParseRows

• The original d3.csv and d3.tsv for loading files have not been renamed.

• There is no more d3.dsv for custom formatters, you can now use d3.dsvFormat("|") to define a new formatter and parser.

Delimiter-Separated Values (d3-dsv)

• Lots of renaming:

  • d3.csv.parse → d3.csvParse
  • d3.csv.parseRows → d3.csvParseRows

• The original d3.csv and d3.tsv for loading files have not been renamed.

• There is no more d3.dsv for custom formatters, you can now use d3.dsvFormat("|") to define a new formatter and parser.

• The parse method now exposes column names:

d3.csv("cars.csv", function(error, data) {
  if (error) throw error;
  console.log(data.columns); // ["Year", "Make", "Model", "Length"]
});

Polygons (d3-polygon)

• d3.geom.polygon is gone and there is no d3.polygon.

• Now using d3.polygonHull(points) which returns the convex hull of the specified points. The returned hull is represented as an array containing a subset of the input points arranged in counterclockwise order.

Polygons (d3-polygon)

• d3.geom.polygon is gone and there is no d3.polygon.

• Now using d3.polygonHull(points) which returns the convex hull of the specified points. The returned hull is represented as an array containing a subset of the input points arranged in counterclockwise order.

Some helper methods to call with the results of polygonHull:

• d3.polygonArea - area of polygon
• d3.polygonCentroid - center point of polygon
• d3.polygonContains - checks if a point is inside of a polygon.
• d3.polygonLength - returns the length of the perimiter.

Example here

Quadtree (d3-quadtree)

A quadtree recursively partitions two-dimensional space into squares, dividing each square into four equally-sized squares. http://bl.ocks.org/mbostock/9078690

• d3.geom.quadtree → d3.quadtree
• Quadtree is no longer a generator. Instead of defining a quadtree function that you pass your data to, you add your data to the quadtree you're generating using the add or addAll methods:

In v3:

var quadtree = d3.geom.quadtree()
    .extent([[0, 0], [width, height]]);
quadtree(data);

In V4:

var quadtree = d3.quadtree()
    .extent([[0, 0], [width, height]])
    .addAll(data);

Quadtree (d3-quadtree)

• Previously the quadtree generator returned the root node, now you can get it by calling quadtree.root.

Quadtree (d3-quadtree)

• Previously the quadtree generator returned the root node, now you can get it by calling quadtree.root.

• The leaf boolean flag on nodes is gone, now you can use node.length to determine if the node has children instead.

Quadtree (d3-quadtree)

• Previously the quadtree generator returned the root node, now you can get it by calling quadtree.root.

• The leaf boolean flag on nodes is gone, now you can use node.length to determine if the node has children instead.

• quadtree.find now takes an optional radius (in screen px) that its search will be restricted to - useful when your quadtree has a lot of points.

Quadtree (d3-quadtree)

• Previously the quadtree generator returned the root node, now you can get it by calling quadtree.root.

• The leaf boolean flag on nodes is gone, now you can use node.length to determine if the node has children instead.

• quadtree.find now takes an optional radius (in screen px) that its search will be restricted to - useful when your quadtree has a lot of points.

• Implementation no longer recursive and much faster.

Other small but notable

• Written in strict mode

Other small but notable

• Written in strict mode

• d3-geo introduces fitSize, the greatest thing since sliced bread

Other small but notable

• Written in strict mode

• d3-geo introduces fitSize, the greatest thing since sliced bread

• The default build is anonymous (aka no global d3 object is exported if AMD or CommonJS is detected.)

Other small but notable

• Written in strict mode

• d3-geo introduces fitSize, the greatest thing since sliced bread

• The default build is anonymous (aka no global d3 object is exported if AMD or CommonJS is detected.)

• Uses only ASCII variable names and ASCII string literals. No more requirement to be explicit about UTF-8.

Other small but notable

• Written in strict mode

• d3-geo introduces fitSize, the greatest thing since sliced bread

• The default build is anonymous (aka no global d3 object is exported if AMD or CommonJS is detected.)

• Uses only ASCII variable names and ASCII string literals. No more requirement to be explicit about UTF-8.

• d3.format now has text formatting: d3.format(">10c")("foo"); // " foo"

Other small but notable

• Written in strict mode

• d3-geo introduces fitSize, the greatest thing since sliced bread

• The default build is anonymous (aka no global d3 object is exported if AMD or CommonJS is detected.)

• Uses only ASCII variable names and ASCII string literals. No more requirement to be explicit about UTF-8.

• d3.format now has text formatting: d3.format(">10c")("foo"); // " foo"

• You can set a default locale based on country for some of your number parsing with d3.formatDefaultLocale link

Other small but notable

• Written in strict mode

• d3-geo introduces fitSize, the greatest thing since sliced bread

• The default build is anonymous (aka no global d3 object is exported if AMD or CommonJS is detected.)

• Uses only ASCII variable names and ASCII string literals. No more requirement to be explicit about UTF-8.

• d3.format now has text formatting: d3.format(">10c")("foo"); // " foo"

• You can set a default locale based on country for some of your number parsing with d3.formatDefaultLocale link

• New random number generators for exponential and uniform distributions.

Other small but notable

• Written in strict mode

• d3-geo introduces fitSize, the greatest thing since sliced bread

• The default build is anonymous (aka no global d3 object is exported if AMD or CommonJS is detected.)

• Uses only ASCII variable names and ASCII string literals. No more requirement to be explicit about UTF-8.

• d3.format now has text formatting: d3.format(">10c")("foo"); // " foo"

• You can set a default locale based on country for some of your number parsing with d3.formatDefaultLocale link

• New random number generators for exponential and uniform distributions.

• d3.xhr is now d3.request, which also supports basic auth by calling .user and .password methods.

Not covered:

• Chord diagrams (d3-chord) changes
• Number formatting (d3-format) changes
• Geography (d3-geo) changes
• Hierarchical layouts (d3-hierarchy) such as treemaps, circle packing etc. changes
• Interpolators (d3-interpolate) - interpolation methods changes
• Time formats (d3-time-format) changes
• Timers (d3-timer) changes
• Voronoi diagrams (d3-voronoi) changes
• Zooming (d3-zoom) changes