CHANGES.md

# Changes in D3 4.0

* [Modules](#modules)
* [Arrays](#arrays-d3-array)
* [Axes](#axes-d3-axis)
* [Brushes](#brushes-d3-brush)
* [Collections](#collections-d3-collection)
* [Colors](#colors-d3-color)
* [Delimiter-Separated Values](#delimiter-separated-values-d3-dsv)
* [Dispatches](#dispatches-d3-dispatch)
* [Dragging](#dragging-d3-drag)
* [Easings](#easings-d3-ease)
* [Forces](#forces-d3-force)
* [Hierarchies](#hierarchies-d3-hierarchy)
* [Interpolators](#interpolators-d3-interpolate)
* [Number Formats](#number-formats-d3-format)
* [Paths](#paths-d3-path)
* [Polygons](#polygons-d3-polygon)
* [Quadtrees](#quadtrees-d3-quadtree)
* [Queues](#queues-d3-queue)
* [Random Numbers](#random-numbers-d3-random)
* [Requests](#requests-d3-request)
* [Scales](#scales-d3-scale)
* [Selections](#selections-d3-selection)
* [Shapes](#shapes-d3-shape)
* [Time Formats](#time-formats-d3-time-format)
* [Time Intervals](#time-intervals-d3-time)
* [Timers](#timers-d3-timer)
* [Transitions](#transitions-d3-transition)
* [Voronoi Diagrams](#voronoi-diagrams-d3-voronoi)
* [Zooming](#zooming-d3-zoom)

N.B.: This document is a work-in-progress. It does not yet cover all API changes.

## Modules

D3 3.x was a monolithic library: the core functionality resided in a single [repository](https://github.com/d3/d3) and was published in a [single file](https://d3js.org/d3.v3.js). It was possible to create a custom build using a [nonstandard tool](https://github.com/mbostock/smash), but not easy and few did. (There were also plugins, but these could only add features and had their own [monolithic repository](https://github.com/d3/d3-plugins).)

D3 4.0 is modular. Instead of one library, D3 is now [many small libraries](https://github.com/d3) that are designed to work together. You can pick and choose which parts to use as you see fit. Each library is maintained in a separate repository, allowing decentralized ownership and independent release cycles. Want to own a new repository in the [D3 organization](https://github.com/d3)? [Let me know!](https://twitter.com/mbostock)

The [default bundle](https://d3js.org/d3.v4.0.0-alpha.45.js) of D3 4.0 conveniently aggregates [about thirty](https://github.com/d3/d3/blob/master/index.js) of these microlibraries.

```html
<script src="https://d3js.org/d3.v4.0.0-alpha.45.min.js"></script>
<script>

d3.select("body")
  .append("p")
    .text("Hello, world!");

</script>
```

But you don’t have to use the default bundle. Custom bundles are useful for applications that use a subset of D3’s features; for example, a React charting library might use D3’s scales and shapes, but use React instead of selections to manipulate the DOM. Or if you’re just using [d3-selection](https://github.com/d3/d3-selection), it’s only 5KB instead of 64KB for the default bundle. You can load D3 microlibraries using vanilla script tags or RequireJS (great for HTTP/2!):

```html
<script src="https://d3js.org/d3-selection.v0.8.min.js"></script>
<script>

d3.select("body")
  .append("p")
    .text("Hello, world!");

</script>
```

You can also `cat` D3 microlibraries into a custom bundle, or use tools such as [Webpack](https://webpack.github.io/) or [Rollup](http://rollupjs.org/) to create [optimized bundles](https://bl.ocks.org/mbostock/bb09af4c39c79cffcde4). The D3 microlibraries are written as [ES6 modules](http://www.2ality.com/2014/09/es6-modules-final.html), and Rollup lets you pick at the symbol level to produce the smallest bundles!

Small files are nice, but modularity is also about making D3 *fun* again. Microlibraries are easier to understand, develop and test. They make it easier for new people to get involved and contribute. They reduce the distinction between a “core module” and a “plugin”, and increase the pace of development in D3 features.

If you don’t care about modularity, you can mostly ignore this change and keep using the default bundle. However, there’s an unavoidable consequence of adopting ES6 modules: every symbol in D3 4.0 now shares a flat namespace rather than the nesting one of D3 3.x. For example, d3.scale.linear is now d3.scaleLinear, and d3.layout.treemap is now d3.treemap. And there have been many other significant improvements to D3’s features! These changes are covered in the sections below. The adoption of ES6 modules means that D3 is now written exclusively in [strict mode](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode).

The default D3 [UMD bundle](https://github.com/umdjs/umd) is now anonymous, rather being named “d3”. No `d3` global is exported if AMD or CommonJS is detected. In a vanilla environment, the D3 microlibraries share the `d3` global, meaning the code you write for the default D3 bundle works identically if you load the modules separately. The generated UMD bundles are no longer stored in the Git repository. Bower has been repointed to [d3-bower](https://github.com/mbostock-bower/d3-bower); you can also find the generated files on [npmcdn](https://npmcdn.com/d3@next/) and attached to the [latest release](https://github.com/d3/d3/releases/latest). The non-minified default bundle is no longer mangled by UglifyJS, making it more readable and preserving inline comments. The use of ES6 modules also improves readability. (Nearly all of the code from D3 3.x has been rewritten and improved!)

D3 3.x used Unicode variable names, such as τ and π, for a concise representation of mathematical operations. A downside of this approach was that a SyntaxError would occur if you loaded the non-minified D3 using ISO-8859-1 instead of UTF-8. D3 3.x also used Unicode string literals, such as the SI-prefix µ for 1e-6. D3 4.0 uses only ASCII variable names and ASCII string literals (see [rollup-plugin-ascii](https://github.com/mbostock/rollup-plugin-ascii)), avoiding these encoding problems.

## Arrays (d3-array)

The new [d3.scan](https://github.com/d3/d3-array#scan) method performs a linear scan of an array, returning the index of the least element according to the specified comparator. This is similar to [d3.min](https://github.com/d3/d3-array#min) and [d3.max](https://github.com/d3/d3-array#max), except you can use it to find the position of an extreme element, rather than just calculate an extreme value.

```js
var data = [
  {name: "Alice", value: 2},
  {name: "Bob", value: 3},
  {name: "Carol", value: 1},
  {name: "Dwayne", value: 5}
];

var i = d3.scan(data, function(a, b) { return a.value - b.value; }); // 2
data[i]; // {name: "Carol", value: 1}
```

The new [d3.ticks](https://github.com/d3/d3-array#ticks) and [d3.tickStep](https://github.com/d3/d3-array#tickStep) methods are useful for generating human-readable numeric ticks. These methods are a low-level alternative to [*continuous*.ticks](https://github.com/d3/d3-scale#continuous_ticks) from [d3-scale](https://github.com/d3/d3-scale). The new implementation is also more accurate, returning the optimal number of ticks as measured by relative error.

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

The [d3.range](https://github.com/d3/d3-array#range) method no longer makes an elaborate attempt to avoid floating-point error when *step* is not an integer. The returned values are strictly defined as *start* + *i* \* *step*, where *i* is an integer. (Learn more about [floating point math](http://0.30000000000000004.com/).) d3.range returns the empty array for infinite ranges, rather than throwing an error.

The method signature for optional accessors has been changed to be more consistent with array methods such as [*array*.forEach](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach): the accessor is passed the current element (*d*), the index (*i*), and the array (*data*), with *this* as undefined. This affects [d3.min](https://github.com/d3/d3-array#min), [d3.max](https://github.com/d3/d3-array#max), [d3.extent](https://github.com/d3/d3-array#extent), [d3.sum](https://github.com/d3/d3-array#sum), [d3.mean](https://github.com/d3/d3-array#mean), [d3.median](https://github.com/d3/d3-array#median), [d3.quantile](https://github.com/d3/d3-array#quantile), [d3.variance](https://github.com/d3/d3-array#variance) and [d3.deviation](https://github.com/d3/d3-array#deviation). The [d3.quantile](https://github.com/d3/d3-array#quantile) method previously did not take an accessor. Some methods with optional arguments now treat those arguments as missing if they are null or undefined, rather than strictly checking arguments.length.

### Histograms

The new [d3.histogram](https://github.com/d3/d3-array#histograms) API replaces d3.layout.histogram. Rather than exposing *bin*.x and *bin*.dx on each returned bin, the histogram exposes *bin*.x0 and *bin*.x1, guaranteeing that *bin*.x0 is exactly equal to *bin*.x1 on the preceeding bin. The “frequency” and “probability” modes are no longer supported; each bin is simply an array of elements from the input data, so *bin*.length is equal to D3 3.x’s *bin*.y in frequency mode. To compute a probability distribution, divide the number of elements in each bin by the total number of elements.

The *histogram*.range method has been renamed [*histogram*.domain](https://github.com/d3/d3-array#histogram_domain) for consistency with scales. The *histogram*.bins method has been renamed [*histogram*.thresholds](https://github.com/d3/d3-array#histogram_thresholds), and no longer accepts an upper value: *n* thresholds will produce *n* + 1 bins. If you specify a desired number of bins rather than thresholds, d3.histogram now uses [d3.ticks](https://github.com/d3/d3-array#ticks) to compute nice bin thresholds. In addition to the default Sturges’ formula, D3 now implements the [Freedman-Diaconis rule](https://github.com/d3/d3-array#thresholdFreedmanDiaconis) and [Scott’s normal reference rule](https://github.com/d3/d3-array#thresholdScott).

## Axes (d3-axis)

To render axes properly in D3 3.x, you needed to style them:

```html
<style>
  
.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.axis text {
  font: 10px sans-serif;
}

</style>
<script>

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

</script>
```

If you didn’t, you saw this:

<img src="https://raw.githubusercontent.com/d3/d3/master/img/axis-v3.png" width="100%" height="105">

D3 4.0 provides default styles and shorter syntax. In place of d3.svg.axis and *axis*.orient, D3 4.0 now provides four constructors for each orientation: [d3.axisTop](https://github.com/d3/d3-axis#axisTop), [d3.axisRight](https://github.com/d3/d3-axis#axisRight), [d3.axisBottom](https://github.com/d3/d3-axis#axisBottom), [d3.axisLeft](https://github.com/d3/d3-axis#axisLeft). You can now pass a scale directly to the axis constructor. So you can reduce all of the above to:

```html
<script>

d3.select(".axis")
    .call(d3.axisBottom(x));

</script>
```

And get this:

<img src="https://raw.githubusercontent.com/d3/d3/master/img/axis-v4.png" width="100%" height="105">

You can still override the styles either through CSS or by modifying the axis elements. The new default axis appearance also offsets the axis by a half-pixel to fix a crisp-edges rendering issue on Safari where the axis would be drawn two-pixels thick.

There’s now an [*axis*.tickArguments](https://github.com/d3/d3-axis#axis_tickArguments) method, as an alternative to [*axis*.ticks](https://github.com/d3/d3-axis#axis_ticks) that also allows the axis tick arguments to be inspect. The [*axis*.tickSize](https://github.com/d3/d3-axis#axis_tickSize) method has been changed to only allow a single argument when setting the tick size; use [*axis*.tickSizeInner](https://github.com/d3/d3-axis#axis_tickSizeInner) or [*axis*.tickSizeOuter](https://github.com/d3/d3-axis#axis_tickSizeOuter) to set the inner and outer tick size separately.

## Brushes (d3-brush)

TODO

* d3.svg.brush, *brush*.x, *brush*.y ↦ d3.brush, d3.brushX, d3.brushY
* *brush*.event ↦ *brush*.move
* *brushstart* event ↦ *start* event
* *brushend* event ↦ *end* event
* add *brush*.handleSize
* add *brush*.filter; ignore right-click by default
* improve the default appearance of the brush
* improve brush interaction (e.g., SHIFT key)
* brushes no longer use scales; they operate in screen coordinates
* brushes no longer store state internally; it is stored on applied elements
* remove *brush*.clamp; always clamps to the brushable region
* consume handled events

## Chords (d3-chord)

TODO

* d3.svg.chord ↦ d3.ribbon
* d3.layout.chord ↦ d3.chord

## Collections (d3-collection)

The [d3.set](https://github.com/d3/d3-collection#set) constructor now accepts an existing set for making a copy, just as [d3.map](https://github.com/d3/d3-collection#map) can be used to copy a map. If you pass an array to d3.set,  you can now also pass an array accessor for extracting values from the array. This accessor takes the standard arguments: the current element (*d*), the index (*i*), and the array (*data*), with *this* undefined. For example:

```js
var yields = [
  {yield: 22.13333, variety: "Manchuria",        year: 1932, site: "Grand Rapids"},
  {yield: 26.76667, variety: "Peatland",         year: 1932, site: "Grand Rapids"},
  {yield: 28.10000, variety: "No. 462",          year: 1931, site: "Duluth"},
  {yield: 38.50000, variety: "Svansota",         year: 1932, site: "Waseca"},
  {yield: 40.46667, variety: "Svansota",         year: 1931, site: "Crookston"},
  {yield: 29.86667, variety: "Peatland",         year: 1931, site: "Morris"},
  {yield: 36.03333, variety: "Peatland",         year: 1932, site: "Waseca"},
  {yield: 34.46667, variety: "Wisconsin No. 38", year: 1931, site: "Grand Rapids"}
];

var sites = d3.set(yields, function(d) { return d.site; }); // ["Grand Rapids", "Duluth", "Waseca", "Crookston", "Morris"]
```

The d3.map constructor also follows the standard array accessor argument pattern.

The *map*.forEach and *set*.forEach methods have been renamed to [*map*.each](https://github.com/d3/d3-collection#map_each) and [*set*.each](https://github.com/d3/d3-collection#set_each) respectively. In addition, the order of arguments for *map*.each has been changed to *value*, *key* and *map*, while the order of arguments for *set*.each is now *value*, *value* and *set*. This is closer to ES6 [*map*.forEach](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/forEach) and [*set*.forEach](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/forEach). Also like ES6 Map and Set, *map*.set and *set*.add now return the current collection (rather than the added value) to facilitate method chaining. New [*map*.clear](https://github.com/d3/d3-collection#map_clear) and [*set*.clear](https://github.com/d3/d3-collection#set_clear) methods can be used to empty collections.

The [*nest*.map](https://github.com/d3/d3-collection#nest_map) method now always returns a d3.map instance. For a plain object, use [*nest*.object](https://github.com/d3/d3-collection#nest_object) instead. When used in conjunction with [*nest*.rollup](https://github.com/d3/d3-collection#nest_rollup), [*nest*.entries](https://github.com/d3/d3-collection#nest_entries) now returns {key, value} objects for the leaf entries, instead of {key, values}.

## Colors (d3-color)

TODO

## Delimiter-Separated Values (d3-dsv)

TODO

* d3.csv.parse ↦ d3.csvParse
* d3.csv.parseRows ↦ d3.csvParseRows
* d3.csv.format ↦ d3.csvFormat
* d3.csv.formatRows ↦ d3.csvFormatRows
* d3.tsv.parse ↦ d3.tsvParse
* d3.tsv.parseRows ↦ d3.tsvParseRows
* d3.tsv.format ↦ d3.tsvFormat
* d3.tsv.formatRows ↦ d3.tsvFormatRows

## Dispatches (d3-dispatch)

TODO

## Dragging (d3-drag)

TODO

* d3.behavior.drag ↦ d3.drag

## Easings (d3-ease)

TODO

## Forces (d3-force)

TODO

* d3.layout.force ↦ d3.forceSimulation

## Geographies (d3-geo)

TODO

* d3.geo.graticule ↦ d3.geoGraticule
* d3.geo.circle ↦ d3.geoCircle
* d3.geo.area ↦ d3.geoArea
* d3.geo.bounds ↦ d3.geoBounds
* d3.geo.centroid ↦ d3.geoCentroid
* d3.geo.distance ↦ d3.geoDistance
* d3.geo.interpolate ↦ d3.geoInterpolate
* d3.geo.length ↦ d3.geoLength
* d3.geo.rotation ↦ d3.geoRotation
* d3.geo.stream ↦ d3.geoStream

## Geographic Projections (d3-geo-projection)

TODO

* d3.geo.path ↦ d3.geoPath

## Hierarchies (d3-hierarchy)

TODO

* d3.layout.cluster ↦ d3.cluster
* d3.layout.hierarchy ↦ d3.hierarchy
* d3.layout.pack ↦ d3.pack
* d3.layout.partition ↦ d3.partition
* d3.layout.tree ↦ d3.tree
* d3.layout.treemap ↦ d3.treemap

## Interpolators (d3-interpolate)

TODO

* d3.interpolators ↦ REMOVED

## Number Formats (d3-format)

TODO

## Paths (d3-path)

TODO

## Polygons (d3-polygon)

TODO

* d3.geom.polygon.area ↦ d3.polygonArea
* d3.geom.polygon.centroid ↦ d3.polygonCentroid
* d3.geom.hull ↦ d3.polygonHull

## Quadtrees (d3-quadtree)

TODO

* d3.geom.quadtree ↦ d3.quadtree

## Random Numbers (d3-random)

TODO

* d3.random.normal ↦ d3.randomNormal
* d3.random.logNormal ↦ d3.randomLogNormal
* d3.random.bates ↦ d3.randomBates
* d3.random.irwinHall ↦ d3.randomIrwinHall

## Requests (d3-request)

TODO

* d3.xhr ↦ d3.request

## Scales (d3-scale)

TODO

* d3.scale.linear ↦ d3.scaleLinear
* d3.scale.sqrt ↦ d3.scaleSqrt
* d3.scale.pow ↦ d3.scalePow
* d3.scale.log ↦ d3.scaleLog
* d3.scale.quantize ↦ d3.scaleQuantize
* d3.scale.threshold ↦ d3.scaleThreshold
* d3.scale.quantile ↦ d3.scaleQuantile
* d3.scale.identity ↦ d3.scaleIdentity
* d3.scale.ordinal ↦ d3.scaleOrdinal
* d3.scale.category10 ↦ d3.schemeCategory10
* d3.scale.category20 ↦ d3.schemeCategory20
* d3.scale.category20b ↦ d3.schemeCategory20b
* d3.scale.category20c ↦ d3.schemeCategory20c
* d3.time.scale ↦ d3.scaleTime

## Selections (d3-selection)

TODO

* immutable; *selection*.data returns a new selection
* only one class of selection; entering nodes are placeholders
* *selection*.enter and *selection*.exit are empty by default (not error)
* *selection*.filter preserves index
* *selection*.append preserves relative order
* no *enter*.append magic; use *selection*.merge
* change how *selection*.data handles duplicate keys
* d3.matcher, d3.selector, d3.creator
* no longer extends Array using prototype injection
* multi-value map methods extracted to d3-selection-multi
* *selection*.raise, *selection*.lower
* *selection*.dispatch
* *selection*.nodes
* d3.local for local variables
* d3.ns.qualify ↦ d3.namespace
* d3.ns.prefix ↦ d3.namespaces

## Shapes (d3-shape)

TODO

* d3.svg.line ↦ d3.line
* d3.svg.line.radial ↦ d3.radialLine
* d3.svg.area ↦ d3.area
* d3.svg.area.radial ↦ d3.radialArea
* d3.svg.arc ↦ d3.arc
* d3.svg.symbol ↦ d3.symbol
* d3.svg.symbolTypes ↦ d3.symbolTypes
* d3.svg.diagonal ↦ REMOVED
* d3.svg.diagonal.radial ↦ REMOVED
* d3.layout.bundle ↦ d3.curveBundle
* d3.layout.stack ↦ d3.stack

## Time Formats (d3-time-format)

TODO

* d3.time.format ↦ d3.timeFormat
* d3.time.format.multi ↦ REMOVED
* d3.time.format.utc ↦ d3.utcFormat
* d3.time.format.iso ↦ d3.isoFormat

## Time Intervals (d3-time)

TODO

* d3.time.interval ↦ d3.timeInterval
* d3.time.day ↦ d3.timeDay
* d3.time.days ↦ d3.timeDays
* d3.time.dayOfYear ↦ d3.timeDay.count
* d3.time.hour ↦ d3.timeHour
* d3.time.hours ↦ d3.timeHours
* d3.time.minute ↦ d3.timeMinute
* d3.time.minutes ↦ d3.timeMinutes
* d3.time.month ↦ d3.timeMonth
* d3.time.months ↦ d3.timeMonths
* d3.time.second ↦ d3.timeSecond
* d3.time.seconds ↦ d3.timeSeconds
* d3.time.sunday ↦ d3.timeSunday
* d3.time.sundays ↦ d3.timeSundays
* d3.time.sundayOfYear ↦ d3.timeSunday.count
* d3.time.monday ↦ d3.timeMonday
* d3.time.mondays ↦ d3.timeMondays
* d3.time.mondayOfYear ↦ d3.timeMonday.count
* d3.time.tuesday ↦ d3.timeTuesday
* d3.time.tuesdays ↦ d3.timeTuesdays
* d3.time.tuesdayOfYear ↦ d3.timeTuesday.count
* d3.time.wednesday ↦ d3.timeWednesday
* d3.time.wednesdays ↦ d3.timeWednesdays
* d3.time.wednesdayOfYear ↦ d3.timeWednesday.count
* d3.time.thursday ↦ d3.timeThursday
* d3.time.thursdays ↦ d3.timeThursdays
* d3.time.thursdayOfYear ↦ d3.timeThursday.count
* d3.time.friday ↦ d3.timeFriday
* d3.time.fridays ↦ d3.timeFridays
* d3.time.fridayOfYear ↦ d3.timeFriday.count
* d3.time.saturday ↦ d3.timeSaturday
* d3.time.saturdays ↦ d3.timeSaturdays
* d3.time.saturdayOfYear ↦ d3.timeSaturday.count
* d3.time.week ↦ d3.timeWeek
* d3.time.weeks ↦ d3.timeWeeks
* d3.time.weekOfYear ↦ d3.timeWeek.count
* d3.time.year ↦ d3.timeYear
* d3.time.years ↦ d3.timeYears
* d3.time.day.utc ↦ d3.utcDay
* d3.time.days.utc ↦ d3.utcDays
* d3.time.dayOfYear.utc ↦ d3.utcDay.count
* d3.time.hour.utc ↦ d3.utcHour
* d3.time.hours.utc ↦ d3.utcHours
* d3.time.minute.utc ↦ d3.utcMinute
* d3.time.minutes.utc ↦ d3.utcMinutes
* d3.time.month.utc ↦ d3.utcMonth
* d3.time.months.utc ↦ d3.utcMonths
* d3.time.second.utc ↦ d3.utcSecond
* d3.time.seconds.utc ↦ d3.utcSeconds
* d3.time.sunday.utc ↦ d3.utcSunday
* d3.time.sundays.utc ↦ d3.utcSundays
* d3.time.sundayOfYear.utc ↦ d3.utcSunday.count
* d3.time.monday.utc ↦ d3.utcMonday
* d3.time.mondays.utc ↦ d3.utcMondays
* d3.time.mondayOfYear.utc ↦ d3.utcMonday.count
* d3.time.tuesday.utc ↦ d3.utcTuesday
* d3.time.tuesdays.utc ↦ d3.utcTuesdays
* d3.time.tuesdayOfYear.utc ↦ d3.utcTuesday.count
* d3.time.wednesday.utc ↦ d3.utcWednesday
* d3.time.wednesdays.utc ↦ d3.utcWednesdays
* d3.time.wednesdayOfYear.utc ↦ d3.utcWednesday.count
* d3.time.thursday.utc ↦ d3.utcThursday
* d3.time.thursdays.utc ↦ d3.utcThursdays
* d3.time.thursdayOfYear.utc ↦ d3.utcThursday.count
* d3.time.friday.utc ↦ d3.utcFriday
* d3.time.fridays.utc ↦ d3.utcFridays
* d3.time.fridayOfYear.utc ↦ d3.utcFriday.count
* d3.time.saturday.utc ↦ d3.utcSaturday
* d3.time.saturdays.utc ↦ d3.utcSaturdays
* d3.time.saturdayOfYear.utc ↦ d3.utcSaturday.count
* d3.time.week.utc ↦ d3.utcWeek
* d3.time.weeks.utc ↦ d3.utcWeeks
* d3.time.weekOfYear.utc ↦ d3.utcWeek.count
* d3.time.year.utc ↦ d3.utcYear
* d3.time.years.utc ↦ d3.utcYears

## Timers (d3-timer)

TODO

* d3.timer.flush ↦ d3.timerFlush

## Transitions (d3-transition)

TODO

## Voronoi Diagrams (d3-voronoi)

TODO

* d3.geom.voronoi ↦ d3.voronoi

## Zooming (d3-zoom)

TODO

* d3.behavior.zoom ↦ d3.zoom