3 files changed, 56 insertions, 2 deletions
diff --git a/web/src/math/Ratio.test.ts b/web/src/math/Ratio.test.ts
new file mode 100644
index 0000000..da6fef2
--- /dev/null
+++ b/web/src/math/Ratio.test.ts
@@ -0,0 +1,27 @@
+import { describe, expect, test } from "vitest";
+import Ratio from "./Ratio";
+
+describe(Ratio, () => {
+  describe(Ratio.prototype.add, () => {
+    test("returns fractions in simplest form", () => {
+      const a = Ratio.fromInteger(0);
+      const b = new Ratio(1, 4);
+
+      const c = a.add(b);
+      expect(c.numerator).toBe(1);
+      expect(c.denominator).toBe(4);
+
+      const d = c.add(b);
+      expect(d.numerator).toBe(1);
+      expect(d.denominator).toBe(2);
+
+      const e = d.add(b);
+      expect(e.numerator).toBe(3);
+      expect(e.denominator).toBe(4);
+
+      const f = e.add(b);
+      expect(f.numerator).toBe(1);
+      expect(f.denominator).toBe(1);
+    });
+  });
+});
diff --git a/web/src/math/Ratio.ts b/web/src/math/Ratio.ts
index 0cca966..e2a1fbf 100644
--- a/web/src/math/Ratio.ts
+++ b/web/src/math/Ratio.ts
@@ -1,3 +1,5 @@
+import { gcd } from ".";
+
 /** Serializable representation of a ratio. */
 export type RatioData = [numerator: number, denominator: number];
 
@@ -25,8 +27,10 @@ export default class Ratio {
       throw new RangeError("Ratio demnominator cannot be zero");
     }
 
-    this.#numerator = numerator;
-    this.#denominator = denominator;
+    const divisor = gcd(numerator, denominator);
+
+    this.#numerator = numerator / divisor;
+    this.#denominator = denominator / divisor;
   }
 
   multiplyRatio(other: Ratio): Ratio {
@@ -63,10 +67,22 @@ export default class Ratio {
     return left < right ? -1 : left > right ? 1 : 0;
   }
 
+  equals(other: Ratio): boolean {
+    return this.compare(other) === 0;
+  }
+
   toNumber(): number {
     return this.numerator / this.denominator;
   }
 
+  toString(): string {
+    return `${this.numerator}/${this.denominator}`;
+  }
+
+  [Symbol.for("nodejs.util.inspect.custom")](): string {
+    return `Ratio { ${this.numerator}/${this.denominator} }`;
+  }
+
   static fromInteger(n: number): Ratio {
     return new Ratio(n, 1);
   }
@@ -78,4 +94,12 @@ export default class Ratio {
   static fromData(ratio: RatioData): Ratio {
     return new Ratio(ratio[0], ratio[1]);
   }
+
+  static min(...ratios: Ratio[]): Ratio {
+    return ratios.reduce((a, b) => (a.compare(b) <= 0 ? a : b));
+  }
+
+  static max(...ratios: Ratio[]): Ratio {
+    return ratios.reduce((a, b) => (a.compare(b) >= 0 ? a : b));
+  }
 }
diff --git a/web/src/math/index.ts b/web/src/math/index.ts
new file mode 100644
index 0000000..70dbb67
--- /dev/null
+++ b/web/src/math/index.ts
@@ -0,0 +1,3 @@
+export function gcd(a: number, b: number): number {
+  return b === 0 ? Math.abs(a) : gcd(b, a % b);
+}