fix: use bignumber.js for sat percentiles

package.json

@@ -51,6 +51,7 @@
     "@fastify/type-provider-typebox": "^2.1.0",
     "@sinclair/typebox": "^0.24.20",
     "@types/node": "^18.13.0",
+    "bignumber.js": "^9.1.1",
     "bitcoinjs-lib": "^6.1.0",
     "env-schema": "^5.2.0",
     "fastify": "^4.3.0",

src/api/util/ordinal-satoshi.ts

@@ -1,3 +1,5 @@
+import BigNumber from 'bignumber.js';
+
 const HALVING_BLOCKS = 210_000;
 const DIFFICULTY_ADJUST_BLOCKS = 2016;
 const INITIAL_SUBSIDY = 50;
@@ -13,6 +15,10 @@ export enum SatoshiRarity {
   mythic = 'mythic',
 }
 
+/**
+ * Ordinal Satoshi calculator. Mostly translated from the original Rust implementation at
+ * https://github.com/casey/ord/blob/master/src/sat.rs
+ */
 export class OrdinalSatoshi {
   public blockHeight: number;
   public cycle: number;
@@ -75,7 +81,8 @@ export class OrdinalSatoshi {
   }
 
   public get percentile(): string {
-    return `${(this.ordinal / (SAT_SUPPLY - 1)) * 100.0}%`;
+    const percentile = new BigNumber((this.ordinal / (SAT_SUPPLY - 1)) * 100.0);
+    return `${percentile.toFixed()}%`;
   }
 
   public get rarity(): SatoshiRarity {

tests/ordinal-satoshi.test.ts

@@ -80,8 +80,7 @@ describe('OrdinalSatoshi', () => {
     expect(sat.epoch).toBe(0);
     expect(sat.name).toBe('nvtdijuwxdx');
     expect(sat.offset).toBe(200);
-    // TODO: Convert scientific notation to number.
-    // expect(sat.percentile).toBe('0.000000000009523809534285719%');
+    expect(sat.percentile).toBe('0.000000000009523809534285719%');
     expect(sat.period).toBe(0);
     expect(sat.blockHeight).toBe(0);
   });