Move binary search to util file

common/calculate-cpmm.ts

@@ -4,6 +4,7 @@ import { LimitBet } from './bet'
 import { CREATOR_FEE, Fees, LIQUIDITY_FEE, PLATFORM_FEE } from './fees'
 import { LiquidityProvision } from './liquidity-provision'
 import { computeFills } from './new-bet'
+import { binarySearch } from './util/algos'
 import { addObjects } from './util/object'
 
 export type CpmmState = {
@@ -139,29 +140,6 @@ export function calculateCpmmAmount(
   return amount
 }
 
-function binarySearch(
-  min: number,
-  max: number,
-  comparator: (x: number) => number
-) {
-  let mid = 0
-  while (true) {
-    mid = min + (max - min) / 2
-
-    // Break once we've reached max precision.
-    if (mid === min || mid === max) break
-
-    const comparison = comparator(mid)
-    if (comparison === 0) break
-    else if (comparison > 0) {
-      max = mid
-    } else {
-      min = mid
-    }
-  }
-  return mid
-}
-
 function calculateAmountToBuyShares(
   state: CpmmState,
   shares: number,

common/util/algos.ts

@@ -0,0 +1,22 @@
+export function binarySearch(
+  min: number,
+  max: number,
+  comparator: (x: number) => number
+) {
+  let mid = 0
+  while (true) {
+    mid = min + (max - min) / 2
+
+    // Break once we've reached max precision.
+    if (mid === min || mid === max) break
+
+    const comparison = comparator(mid)
+    if (comparison === 0) break
+    else if (comparison > 0) {
+      max = mid
+    } else {
+      min = mid
+    }
+  }
+  return mid
+}