feat(math): add simplifyRatio()

thi-ng · Jan 28, 2019 · 31e369b · 31e369b
1 parent 226645f
commit 31e369b
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diff --git a/packages/math/src/index.ts b/packages/math/src/index.ts
@@ -7,5 +7,6 @@ export * from "./interval";
 export * from "./min-error";
 export * from "./mix";
 export * from "./prec";
+export * from "./ratio";
 export * from "./solve";
 export * from "./step";
diff --git a/packages/math/src/ratio.ts b/packages/math/src/ratio.ts
@@ -0,0 +1,18 @@
+export const simplifyRatio =
+    (num: number, denom: number) => {
+        let e1 = Math.abs(num);
+        let e2 = Math.abs(denom);
+        while (true) {
+            if (e1 < e2) {
+                const t = e1;
+                e1 = e2;
+                e2 = t;
+            }
+            const r = e1 % e2;
+            if (r) {
+                e1 = r;
+            } else {
+                return [num / e2, denom / e2];
+            }
+        }
+    };