Scale convenience constructors.

[mbostock]

It’d be lovely to say

x = d3.scaleLinear(domain, range)

as shorthand for

x = d3.scaleLinear().domain(domain).range(range)

Fleshing out the full list, including the new transformed scales #156:

• scaleBand() // domain = [], range = [0, 1]
• scaleBand(range) // domain = []
• scaleBand(domain, range)
• scalePoint() // domain = [], range = [0, 1]
• scalePoint(range) // domain = []
• scalePoint(domain, range)
• scaleIdentity() // domain = range = [0, 1]
• scaleIdentity(range) // domain = range
• scaleLinear() // domain = [0, 1], range = [0, 1]
• scaleLinear(range) // domain = [0, 1]
• scaleLinear(domain, range)
• scaleLog() // domain = [1, 10], range = [0, 1], base = 10
• scaleLog(range) // domain = [1, 10], base = 10
• scaleLog(domain, range) // base = 10
• scaleOrdinal() // domain = [], range = []
• scaleOrdinal(range) // domain = []
• scaleOrdinal(domain, range)
• scalePow() // domain = [0, 1], range = [0, 1], exponent = 1
• scalePow(range) // domain = [0, 1], exponent = 1
• scalePow(domain, range) // exponent = 1
• scaleSqrt() // domain = [0, 1], range = [0, 1]
• scaleSqrt(range) // domain = [0, 1]
• scaleSqrt(domain, range)
• scaleQuantile() // domain = [], range = []
• scaleQuantile(range) // domain = []
• scaleQuantile(domain, range)
• scaleQuantize() // domain = [0.5], range = [0, 1]
• scaleQuantize(range) // domain = [0.5]
• scaleQuantize(domain, range)
• scaleThreshold() // domain = [0.5], range = [0, 1]
• scaleThreshold(range) // domain = [0.5]
• scaleThreshold(domain, range)
• scaleTime() // domain = [2000-01-01, 2000-01-02], range = [0, 1]
• scaleTime(range) // domain = [2000-01-01, 2000-01-02]
• scaleTime(domain, range)
• scaleUtc() // domain = [2000-01-01Z, 2000-01-02Z], range = [0, 1]
• scaleUtc(range) // domain = [2000-01-01Z, 2000-01-02Z]
• scaleUtc(domain, range)
• scaleSequential() // interpolator = identity
• scaleSequential(interpolator) // domain = [0, 1]
• scaleSequential(domain, interpolator)
• scaleSequentialLog() // interpolator = identity, domain = [1, 10], base = 10
• scaleSequentialLog(interpolator) // domain = [1, 10], base = 10
• scaleSequentialLog(domain, interpolator) // base = 10
• scaleSequentialPow() // interpolator = identity, domain = [0, 1], exponent = 1
• scaleSequentialPow(interpolator) // domain = [0, 1], exponent = 1
• scaleSequentialPow(domain, interpolator) // exponent = 1
• scaleSequentialSqrt() // interpolator = identity, domain = [0, 1]
• scaleSequentialSqrt(interpolator) // domain = [0, 1]
• scaleSequentialSqrt(domain, interpolator)
• scaleSequentialQuantile() // interpolator = identity, domain = []
• scaleSequentialQuantile(interpolator) // domain = []
• scaleSequentialQuantile(domain, interpolator)
• scaleDiverging() // interpolator = identity, domain = [0, 0.5, 1]
• scaleDiverging(interpolator) // domain = [0, 0.5, 1]
• scaleDiverging(domain, interpolator)
• scaleDivergingLog() // interpolator = identity, domain = [0.1, 1, 10], base = 10
• scaleDivergingLog(interpolator) // domain = [0.1, 1, 10], base = 10
• scaleDivergingLog(domain, interpolator) // base = 10
• scaleDivergingPow() // interpolator = identity, domain = [0, 0.5, 1], exponent = 1
• scaleDivergingPow(interpolator) // domain = [0, 0.5, 1], exponent = 1
• scaleDivergingPow(domain, interpolator) // exponent = 1
• scaleDivergingSqrt() // interpolator = identity, domain = [0, 0.5, 1]
• scaleDivergingSqrt(interpolator) // domain = [0, 0.5, 1]
• scaleDivergingSqrt(domain, interpolator)

Bold are existing scale constructors in master.

[mbostock]

68 70 89 67 62 constructors! 😮 23 existing constructors checked.

[mbostock]

An additional 22 variants if we want to allow the log base and pow exponent specified in the constructor—but I don’t think it’s worth the added complexity.

• scaleLog(base) // domain = [1, 10], range = [0, 1]
• scaleLog(range, base) // domain = [1, 10]
• scaleLog(domain, range, base)
• scalePow(exponent) // domain = [0, 1], range = [0, 1]
• scalePow(range, exponent) // domain = [0, 1]
• scalePow(domain, range, exponent)
• scaleSequentialLog(base) // interpolator = identity, domain = [1, 10]
• scaleSequentialLog(interpolator, base) // domain = [1, 10]
• scaleSequentialLog(domain, base) // interpolator = identity
• scaleSequentialLog(domain, interpolator, base)
• scaleSequentialPow(exponent) // interpolator = identity, domain = [1, 10]
• scaleSequentialPow(interpolator, exponent) // domain = [0, 1]
• scaleSequentialPow(domain, exponent) // interpolator = identity
• scaleSequentialPow(domain, interpolator, exponent)
• scaleDivergingLog(base) // interpolator = identity, domain = [0.1, 1, 10]
• scaleDivergingLog(interpolator, base) // domain = [0.1, 1, 10]
• scaleDivergingLog(domain, base) // interpolator = identity
• scaleDivergingLog(domain, interpolator, base)
• scaleDivergingPow(exponent) // interpolator = identity, domain = [0, 0.5, 1]
• scaleDivergingPow(interpolator, exponent) // domain = [0, 0.5, 1]
• scaleDivergingPow(domain, exponent) // interpolator = identity
• scaleDivergingPow(domain, interpolator, exponent)

[mbostock]

An additional 5 variants if we want to specify the domain but not interpolator—which again, I don’t think is worth it.

• scaleSequentialLog(domain) // interpolator = identity, base = 10
• scaleSequentialPow(domain) // interpolator = identity, exponent = 1
• scaleDivergingPow(domain) // interpolator = identity, exponent = 1
• scaleDivergingSqrt(domain) // interpolator = identity
• scaleDivergingLog(domain) // interpolator = identity, base = 10

[mbostock]

The top approach has a nice property in that all scales have the same three constructor forms:

• a default constructor (0 arguments)
• a range-only constructor (where range = interpolator as appropriate)
• a domain-and-range constructor