• Adopt type: module. #246
• Adopt InternMap for ordinal scale domains. #235
• Update dependencies.
• Make build reproducible.

This package now requires Node.js 12 or higher. For more, please read Sindre Sorhus’s FAQ.

• Adopt d3.timeTicks and d3.utcTicks.

• Fix handling of null in quantitative scales; it is now considered an “unknown” value. #241

• Fix performance regression with d3.scaleQuantile. #224 Thanks @ilijapuaca!

• Fix continuous.nice to ensure that niced domains always span ticks. Thanks, @domoritz! #209
• Update dependencies.

• Fix log.ticks for small domains. #192
• Fix d3-interpolate dependency version. #197 Thanks, @third774!

• Add diverging.rangeRound.
• Add sequential.rangeRound.
• Add sequentialQuantile.quantiles.
• diverging.range can now be used to set the interpolator.
• sequential.range can now be used to set the interpolator.
• d3.scaleSequential can now accept a range array in place of an interpolator.
• d3.scaleDiverging can now accept a range array in place of an interpolator.

• Add d3.scaleRadial.
• Add sequential.range (for compatibility with d3-axis).
• Fix log.ticks for small domains. #44
• Fix scale.clamp for sequential quantile scales. Thanks, @Fil!
• Fix scale.clamp for continuous scales with more domain values than range values.
• Fix diverging scales with descending domains. Thanks, @Fil!
• Adopt explicit paths for imports.

• Remove deprecated step argument from time.ticks and time.nice. #183

• Accept iterables wherever appropriate. #163
• Adopt ES Map; drop d3-collection dependency. #165

Note: this release adopts ES2015 language features such as for-of and drops support for older browsers, including IE. If you need to support pre-ES2015 environments, you should stick with d3-scale 2.x or use a transpiler.

• Add missing export for d3.scaleDivergingSymlog.

• Revert adoption of ES Map; this will happen in a major release.

• Add domain and range (or interpolator) convenience constructors for all scale types. (#157)
• Add default constructors for sequential and diverging scales. (#159)
• Add d3.tickFormat. (#148)
• Add d3.scaleSymlog. (#105)
• Add transformed sequential scales (e.g., d3.scaleSequentialLog). (#62)
• Add transformed diverging scales (e.g., d3.scaleDivergingLog). (#62)
• Add d3.scaleSequentialQuantile for p-quantiles. (#93)
• Add scale.unknown for all scale types. (#97)
• Allow unlimited band.paddingOuter and point.padding. (#102)
• For collapsed domains, use midpoint of domain or range rather than start. (#117)
• Clarify documentation. (#123, #132)

• Add d3.scaleDiverging.
• Fix treatment of degenerate domains in d3.scaleSequential. (#130)

• Move color schemes to d3-scale-chromatic.
• Remove category20* color schemes. (#96)

• Don’t try to generate sub-millisecond ticks for time scales. Thanks, @FracturedShader!

• Fix rounding errors in continuous.nice. (#81)
• Fix inconsistency between continuous.ticks and continous.nice. Thanks, @danielyule! (#104)

• Add module entry point to package.json.

• Deprecate the optional step argument to time.ticks; use interval.every instead.

• First stable release.
• Fix order of ticks with log scales with huge descending domains.
• Add sequential.interpolator.

Changes since D3 3.x

Pursuant to the great namespace flattening:

• 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.time.scale ↦ d3.scaleTime
• d3.time.scale.utc ↦ d3.scaleUtc

Scales now generate ticks in the same order as the domain: if you have a descending domain, you now get descending ticks. This change affects the order of tick elements generated by axes. For example:

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

Log tick formatting now assumes a default count of ten, not Infinity, if not specified. Log scales with domains that span many powers (such as from 1e+3 to 1e+29) now return only one tick per power rather than returning base ticks per power. Non-linear quantitative scales are slightly more accurate.

You can now control whether an ordinal scale’s domain is implicitly extended when the scale is passed a value that is not already in its domain. By default, ordinal.unknown is d3.scaleImplicit, causing unknown values to be added to the domain:

var x = d3.scaleOrdinal()
    .domain([0, 1])
    .range(["red", "green", "blue"]);

x.domain(); // [0, 1]
x(2); // "blue"
x.domain(); // [0, 1, 2]

By setting ordinal.unknown, you instead define the output value for unknown inputs. This is particularly useful for choropleth maps where you want to assign a color to missing data.

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

x.domain(); // [0, 1]
x(2); // undefined
x.domain(); // [0, 1]

The ordinal.rangeBands and ordinal.rangeRoundBands methods have been replaced with a new subclass of ordinal scale: band scales. The following code in 3.x:

var x = d3.scaleOrdinal()
    .domain(["a", "b", "c"])
    .rangeBands([0, width]);

Is equivalent to this in 4.0:

var x = d3.scaleBand()
    .domain(["a", "b", "c"])
    .range([0, width]);

The new band.padding, band.paddingInner and band.paddingOuter methods replace the optional arguments to ordinal.rangeBands. The new band.bandwidth and band.step methods replace ordinal.rangeBand. There’s also a new band.align method which you can use to control how the extra space outside the bands is distributed, say to shift columns closer to the y-axis.

Similarly, the ordinal.rangePoints and ordinal.rangeRoundPoints methods have been replaced with a new subclass of ordinal scale: point scales. The following code in 3.x:

var x = d3.scaleOrdinal()
    .domain(["a", "b", "c"])
    .rangePoints([0, width]);

Is equivalent to this in 4.0:

var x = d3.scalePoint()
    .domain(["a", "b", "c"])
    .range([0, width]);

The new point.padding method replaces the optional padding argument to ordinal.rangePoints. Like ordinal.rangeBand with ordinal.rangePoints, the point.bandwidth method always returns zero; a new point.step method returns the interval between adjacent points.

The ordinal scale constructor now takes an optional range for a shorter alternative to ordinal.range. This is especially useful now that the categorical color scales have been changed to simple arrays of colors rather than specialized ordinal scale constructors:

• d3.scale.category10 ↦ d3.schemeCategory10
• d3.scale.category20 ↦ d3.schemeCategory20
• d3.scale.category20b ↦ d3.schemeCategory20b
• d3.scale.category20c ↦ d3.schemeCategory20c

The following code in 3.x:

var color = d3.scaleCategory10();

Is equivalent to this in 4.0:

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

Sequential scales, are a new class of scales with a fixed output interpolator instead of a range. Typically these scales are used to implement continuous sequential or diverging color schemes. Inspired by Matplotlib’s new perceptually-motived colormaps, 4.0 now features viridis, inferno, magma, plasma interpolators for use with sequential scales. Using d3.quantize, these interpolators can also be applied to quantile, quantize and threshold scales.

<img src="https://raw.githubusercontent.com/d3/d3-scale/master/img/viridis.png" width="100%" height="40" alt="viridis"> <img src="https://raw.githubusercontent.com/d3/d3-scale/master/img/inferno.png" width="100%" height="40" alt="inferno"> <img src="https://raw.githubusercontent.com/d3/d3-scale/master/img/magma.png" width="100%" height="40" alt="magma"> <img src="https://raw.githubusercontent.com/d3/d3-scale/master/img/plasma.png" width="100%" height="40" alt="plasma">

4.0 also ships new Cubehelix schemes, including Dave Green’s default and a cyclical rainbow inspired by Matteo Niccoli:

<img src="https://raw.githubusercontent.com/d3/d3-scale/master/img/cubehelix.png" width="100%" height="40" alt="cubehelix"> <img src="https://raw.githubusercontent.com/d3/d3-scale/master/img/rainbow.png" width="100%" height="40" alt="rainbow"> <img src="https://raw.githubusercontent.com/d3/d3-scale/master/img/warm.png" width="100%" height="40" alt="warm"> <img src="https://raw.githubusercontent.com/d3/d3-scale/master/img/cool.png" width="100%" height="40" alt="cool">

For even more sequential and categorical color schemes, see d3-scale-chromatic.

For an introduction to scales, see Introducing d3-scale.

See CHANGES for all D3 changes since 3.x.

• Fix d3.interpolateCubehelixDefault (#68).

• Fix time.domain for valid numbers but invalid dates (#65).

• Export to the global d3 in vanilla environments (d3/d3#2840).

• You can now pass an optional range to d3.scaleOrdinal.
• Replace d3.scaleCategory10 with d3.schemeCategory10.
• Replace d3.scaleCategory20 with d3.schemeCategory20.
• Replace d3.scaleCategory20b with d3.schemeCategory20b.
• Replace d3.scaleCategory20c with d3.schemeCategory20c.
• Replace d3.scaleRainbow with d3.interpolateRainbow.
• Replace d3.scaleWarm with d3.interpolateWarm.
• Replace d3.scaleCool with d3.interpolateCool.
• Replace d3.scaleInferno with d3.interpolateInferno.
• Replace d3.scaleMagma with d3.interpolateMagma.
• Replace d3.scalePlasma with d3.interpolatePlasma.
• Replace d3.scaleViridis with d3.interpolateViridis.

• Add d3.scaleSequential (#56).
• Optimize continuous scales to create interpolators lazily.

• Update d3-interpolate to 0.8.
• Update d3-collection to 0.2.

• time.tickFormat now takes (and ignores) a suggested tick count (#57).

• Update d3-interpolate to 0.7.

• Update d3-interpolate to 0.6.

• Remove some global state to avoid work on initialization.

• Update d3-color to 0.4.

• Remove binding of continuous.interpolate parameters.

• Fix log.tickFormat when no count is specified; it now defaults to 10.

• Fix crash in continuous.tickFormat when the domain is invalid.

• Update dependencies.
• Prefix exported symbols with “scale”.

• Ordinal scales have been redesigned! 💥
• Add band and point scales.
• continuous.interpolate now takes optional parameters.
• The rainbow scale now takes a two- (not three-) element domain.
• Add warm and cool sequential color scales.
• The viridis color scales are now optimized sequential (not quantize) scales.
• Improve the README.

• Add viridis, inferno, magma and plasma sequential color scales.
• Quantitative scales now return ticks in descending order for descending domains.
• Non-linear quantitative scales are now more accurate.
• Clamped scales can no longer return a value slightly outside of the domain when inverting.
• log.ticks now filters powers-of-base ticks for very large domains.
• log.tickFormat is now more accurate.
• Quantize scales are now more accurate.
• quantize.invertExtent is now consistent with quantize.

• time.ticks and time.nice no longer take an interval name; use a time interval instead.

• Define d3-scale module (and d3_scale global), not scale.
• The d3-arrays, d3-color, d3-format, d3-interpolate, d3-time and d3-time-format dependencies are no longer inlined.

• Fix name of exported global (scale) in provided UMD bundles.

• Adjusted the package.json definition for npm users.

• Allow custom time intervals with time.ticks and time.nice.

• Added time and utcTime scales.