| 8 | import sturges from "./threshold/sturges.js"; |
| 9 | |
| 10 | export default function bin() { |
| 11 | var value = identity, |
| 12 | domain = extent, |
| 13 | threshold = sturges; |
| 14 | |
| 15 | function histogram(data) { |
| 16 | if (!Array.isArray(data)) data = Array.from(data); |
| 17 | |
| 18 | var i, |
| 19 | n = data.length, |
| 20 | x, |
| 21 | step, |
| 22 | values = new Array(n); |
| 23 | |
| 24 | for (i = 0; i < n; ++i) { |
| 25 | values[i] = value(data[i], i, data); |
| 26 | } |
| 27 | |
| 28 | var xz = domain(values), |
| 29 | x0 = xz[0], |
| 30 | x1 = xz[1], |
| 31 | tz = threshold(values, x0, x1); |
| 32 | |
| 33 | // Convert number of thresholds into uniform thresholds, and nice the |
| 34 | // default domain accordingly. |
| 35 | if (!Array.isArray(tz)) { |
| 36 | const max = x1, tn = +tz; |
| 37 | if (domain === extent) [x0, x1] = nice(x0, x1, tn); |
| 38 | tz = ticks(x0, x1, tn); |
| 39 | |
| 40 | // If the domain is aligned with the first tick (which it will by |
| 41 | // default), then we can use quantization rather than bisection to bin |
| 42 | // values, which is substantially faster. |
| 43 | if (tz[0] <= x0) step = tickIncrement(x0, x1, tn); |
| 44 | |
| 45 | // If the last threshold is coincident with the domain’s upper bound, the |
| 46 | // last bin will be zero-width. If the default domain is used, and this |
| 47 | // last threshold is coincident with the maximum input value, we can |
| 48 | // extend the niced upper bound by one tick to ensure uniform bin widths; |
| 49 | // otherwise, we simply remove the last threshold. Note that we don’t |
| 50 | // coerce values or the domain to numbers, and thus must be careful to |
| 51 | // compare order (>=) rather than strict equality (===)! |
| 52 | if (tz[tz.length - 1] >= x1) { |
| 53 | if (max >= x1 && domain === extent) { |
| 54 | const step = tickIncrement(x0, x1, tn); |
| 55 | if (isFinite(step)) { |
| 56 | if (step > 0) { |
| 57 | x1 = (Math.floor(x1 / step) + 1) * step; |
| 58 | } else if (step < 0) { |
| 59 | x1 = (Math.ceil(x1 * -step) + 1) / -step; |
| 60 | } |
| 61 | } |
| 62 | } else { |
| 63 | tz.pop(); |
| 64 | } |
| 65 | } |
| 66 | } |
| 67 | |