add selectRangeStrategy

Author: rwv

src/get/manager/DownloadManger.ts

@@ -24,7 +24,7 @@ export class DownloadManger {
     requestConfig.logger.info(`Workers Count: ${this.workers.length}`)
 
     const contentLength = getContentLength(metadata.headers)
-    this.rangeProvider = new RangeProvider(contentLength, this.requestConfig.segmentStrategy)
+    this.rangeProvider = new RangeProvider(contentLength, this.requestConfig.segmentStrategy, this.requestConfig.selectRangeStrategy)
     requestConfig.logger.info(`Content length: ${contentLength}`)
 
     this.streamer = new DownloadStreamer(this.rangeProvider.maxRangeIndex, requestConfig?.init?.signal)

src/get/range/selectRangeStrategy.ts

@@ -1,5 +1,4 @@
 import type { RangeIndex } from './types'
-import { getMapMinOrZero } from './utils'
 
 const threshold = 10
 
@@ -15,3 +14,24 @@ export function defaultSelectRangeStrategy (
 
   return minRangeIndex
 }
+
+function getMapMinOrZero<T> (map: Map<T, number>): T {
+  let minKey: T | undefined
+  let minVal: number | undefined
+  for (const [key, val] of map) {
+    if (val === 0) {
+      return key
+    }
+
+    if (minVal === undefined || val < minVal) {
+      minKey = key
+      minVal = val
+    }
+  }
+
+  if (minKey === undefined) {
+    throw new Error('Map is empty')
+  }
+
+  return minKey
+}

src/get/range/utils.ts

@@ -39,10 +39,14 @@ export class GETRequestConfig {
   }
 
   get chunkCallback (): ChunkCallback {
-    return this.fastFetchConfig?.chunkCallback ?? (() => undefined)
+    return this.fastFetchConfig?.chunkCallback ?? defaultConfig.chunkCallback
   }
 
-  get segmentStrategy (): ((contentLength: number) => Array<[number, number]>) | undefined {
-    return this.fastFetchConfig?.segmentStrategy
+  get segmentStrategy (): ((contentLength: number) => Array<[number, number]>) {
+    return this.fastFetchConfig?.segmentStrategy ?? defaultConfig.segmentStrategy
+  }
+
+  get selectRangeStrategy (): ((downloaderCounter: Map<number, number>) => number) {
+    return this.fastFetchConfig?.selectRangeStrategy ?? defaultConfig.selectRangeStrategy
   }
 }

src/get/request/RequestConfig.ts

@@ -1,4 +1,11 @@
+import { defaultSelectRangeStrategy } from '../range/selectRangeStrategy'
+import { defaultSegmentStrategy } from '../range/segmentStrategy'
+
 export const defaultConfig = {
   maxRetries: 5,
-  retryDelay: 3000
+  retryDelay: 3000,
+  sequential: false,
+  chunkCallback: () => undefined,
+  selectRangeStrategy: defaultSelectRangeStrategy,
+  segmentStrategy: defaultSegmentStrategy
 } as const

src/get/request/defaultConfig.ts

@@ -11,6 +11,7 @@ export interface FastFetchGetConfig {
   logger?: Partial<Logger>
   chunkCallback?: ChunkCallback
   segmentStrategy?: (contentLength: number) => Array<[number, number]>
+  selectRangeStrategy?: (downloaderCounter: Map<number, number>) => number
 }
 
 interface FastFetchGETInit {