New unicode emoji processor

scripts/emoji-surrogates-statistics.js

@@ -0,0 +1,77 @@
+// @ts-check
+
+const fs = require("fs")
+const {join} = require("path")
+const s = fs.readFileSync(join(__dirname, "..", "src", "m2d", "converters", "emojis.txt"), "utf8").split("\n").map(x => encodeURIComponent(x))
+const searchPattern = "%EF%B8%8F"
+
+/**
+ * adapted from es.map.group-by.js in core-js
+ * @template K,V
+ * @param {V[]} items
+ * @param {(item: V) => K} fn
+ * @returns {Map<K, V[]>}
+ */
+function groupBy(items, fn) {
+	var map = new Map();
+	for (const value of items) {
+		var key = fn(value);
+		if (!map.has(key)) map.set(key, [value]);
+		else map.get(key).push(value);
+	}
+	return map;
+}
+
+/**
+ * @param {number[]} items
+ * @param {number} width
+ */
+function xhistogram(items, width) {
+	const chars = " ▏▎▍▌▋▊▉"
+	const max = items.reduce((a, c) => c > a ? c : a, 0)
+	return items.map(v => {
+		const p = v / max * (width-1)
+		return (
+			Array(Math.floor(p)).fill("█").join("") /* whole part */
+			+ chars[Math.ceil((p % 1) * (chars.length-1))] /* decimal part */
+		).padEnd(width)
+	})
+}
+
+/**
+ * @param {number[]} items
+ * @param {[number, number]} xrange
+ */
+function yhistogram(items, xrange, printHeader = false) {
+	const chars = "░▁_▂▃▄▅▆▇█"
+	const ones = "₀₁₂₃₄₅₆₇₈₉"
+	const tens = "0123456789"
+	const xy = []
+	let max = 0
+	/** value (x) -> frequency (y) */
+	const grouped = groupBy(items, x => x)
+	for (let i = xrange[0]; i <= xrange[1]; i++) {
+		if (printHeader) {
+			if (i === -1) process.stdout.write("-")
+			else if (i.toString().at(-1) === "0") process.stdout.write(tens[i/10])
+			else process.stdout.write(ones[i%10])
+		}
+		const y = grouped.get(i)?.length ?? 0
+		if (y > max) max = y
+		xy.push(y)
+	}
+	if (printHeader) console.log()
+	return xy.map(y => chars[Math.ceil(y / max * (chars.length-1))]).join("")
+}
+
+const grouped = groupBy(s, x => x.length)
+const sortedGroups = [...grouped.entries()].sort((a, b) => b[0] - a[0])
+let length = 0
+const lengthHistogram = xhistogram(sortedGroups.map(v => v[1].length), 10)
+for (let i = 0; i < sortedGroups.length; i++) {
+	const [k, v] = sortedGroups[i]
+	const l = lengthHistogram[i]
+	const h = yhistogram(v.map(x => x.indexOf(searchPattern)), [-1, k - searchPattern.length], i === 0)
+	if (i === 0) length = h.length + 1
+	console.log(`${h.padEnd(length, i % 2 === 0 ? "⸱" : " ")}length ${k.toString().padEnd(3)} ${l} ${v.length}`)
+}