Refactor

Consolidate puid config checks

Author: dingosky

src/lib/bits.ts

@@ -19,8 +19,6 @@
 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
-import crypto from 'crypto'
-
 import encoder from './encoder'
 import { entropyBitsPerChar } from './entropy'
 
@@ -140,22 +138,7 @@ const fillEntropy = (entropyBits: EntropyBits, entropyFunction: EntropyFunction)
   }
 }
 
-const selectEntropyFunction = (puidConfig: PuidConfig): EntropyFunction => {
-  if (puidConfig.entropyValues) {
-    return [true, puidConfig.entropyValues as EntropyByValues]
-  } else if (puidConfig.entropyBytes) {
-    return [false, puidConfig.entropyBytes as EntropyByBytes]
-  } else {
-    return [false, crypto.randomBytes]
-    // [true, crypto.getRandomValues]
-  }
-}
-
-export default (puidLen: number, puidChars: string, puidConfig: PuidConfig): PuidBitsMuncherResult => {
-  if (puidConfig.entropyBytes && puidConfig.entropyValues) {
-    return { error: new Error('Cannot specify both entropyBytes and entropyValues functions') }
-  }
-
+export default (puidLen: number, puidChars: string, entropyFunction: EntropyFunction): PuidBitsMuncherResult => {
   const nBitsPerChar = bitsPerChar(puidChars)
   const nBitsPerPuid = nBitsPerChar * puidLen
   const nBytesPerPuid = ceil(nBitsPerPuid / 8)
@@ -164,12 +147,13 @@ export default (puidLen: number, puidChars: string, puidConfig: PuidConfig): Pui
   const entropyBuffer = new ArrayBuffer(bufferLen)
   const entropyBits: EntropyBits = [8 * bufferLen, entropyBuffer]
   const entropyBytes = new Uint8Array(entropyBuffer)
-  const entropyFunction = selectEntropyFunction(puidConfig)
 
   const charsEncoder = encoder(puidChars)
   const puidEncoded = (value: number) => String.fromCharCode(charsEncoder(value))
 
-  if (isPow2(puidChars.length)) {
+  const nChars = puidChars.length
+  
+  if (isPow2(nChars)) {
     // When chars count is a power of 2, sliced bits always yield a valid char
     const mapper = new Array(puidLen).fill(0).map((zero, ndx) => zero + ndx)
 
@@ -187,7 +171,7 @@ export default (puidLen: number, puidChars: string, puidConfig: PuidConfig): Pui
     return { success: bitsMuncher }
   }
 
-  const nChars = puidChars.length
+  
   const nEntropyBits = 8 * entropyBytes.length
   const puidShifts = bitShifts(puidChars)
 

src/lib/puid.ts

@@ -20,6 +20,8 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+import crypto from 'crypto'
+
 import muncher from './bits'
 import { Chars, charsName, validChars } from './chars'
 import { entropyBits, entropyBitsPerChar } from './entropy'
@@ -28,6 +30,17 @@ const round2 = (f: number): number => round(f * 100) / 100
 
 const { ceil, round } = Math
 
+const selectEntropyFunction = (puidConfig: PuidConfig): EntropyFunction => {
+  if (puidConfig.entropyValues) {
+    return [true, puidConfig.entropyValues as EntropyByValues]
+  } else if (puidConfig.entropyBytes) {
+    return [false, puidConfig.entropyBytes as EntropyByBytes]
+  } else {
+    return [false, crypto.randomBytes]
+    // [true, crypto.getRandomValues]
+  }
+}
+
 /**
  * Create `puid` generating function
  *
@@ -88,6 +101,10 @@ export default (puidConfig: PuidConfig = {}): PuidResult => {
   if (!puidConfig.total && puidConfig.risk) return { error: new Error('Total and risk must be specified together') }
   if (puidConfig.total && puidConfig.bits) return { error: new Error('Cannot specify both total/risk and bits') }
 
+  if (puidConfig.entropyBytes && puidConfig.entropyValues) {
+    return { error: new Error('Cannot specify both entropyBytes and entropyValues functions') }
+  }
+
   const puidEntropyBits =
     puidConfig.total && puidConfig.risk
       ? entropyBits(puidConfig.total, puidConfig.risk)
@@ -96,7 +113,7 @@ export default (puidConfig: PuidConfig = {}): PuidResult => {
   const puidLen = round(ceil(puidEntropyBits / puidBitsPerChar))
   const ere = (puidBitsPerChar * puidChars.length) / (8 * Buffer.byteLength(puidChars))
 
-  const { error: bitsMuncherError, success: bitsMuncher } = muncher(puidLen, puidChars, puidConfig)
+  const { error: bitsMuncherError, success: bitsMuncher } = muncher(puidLen, puidChars, selectEntropyFunction(puidConfig))
   if (bitsMuncherError) return { error: bitsMuncherError }
 
   const puid: Puid = (): string => bitsMuncher()