feat: add dashjoin.js

Author: coolaj86

public/dashjoin.js

@@ -0,0 +1,37 @@
+var DashJoin = ('object' === typeof module && exports) || {};
+(function (window, DashJoin) {
+	'use strict';
+
+	const DENOM_LOWEST = 100001;
+	const PREDENOM_MIN = DENOM_LOWEST + 193;
+
+	DashJoin.DENOM_LOWEST = DENOM_LOWEST;
+	DashJoin.PREDENOM_MIN = PREDENOM_MIN;
+	DashJoin.DENOMS = [
+		100001, //      0.00100001
+		1000010, //     0.01000010
+		10000100, //    0.10000100
+		100001000, //   1.00001000
+		1000010000, // 10.00010000
+	];
+	let reverseDenoms = DashJoin.DENOMS.slice(0);
+	reverseDenoms.reverse();
+
+	// Ask Niles if there's an layman-ish obvious way to do this
+	DashJoin.getDenom = function (sats) {
+		for (let denom of reverseDenoms) {
+			let isDenom = sats === denom;
+			if (isDenom) {
+				return isDenom;
+			}
+		}
+
+		return 0;
+	};
+
+	//@ts-ignore
+	window.DashJoin = DashJoin;
+})(globalThis.window || {}, DashJoin);
+if ('object' === typeof module) {
+	module.exports = DashJoin;
+}