keep min package versions from deletion

src/delete.ts

@@ -15,7 +15,15 @@ export function getVersionIds(input: Input): Observable<string[]> {
       input.packageName,
       input.numOldVersionsToDelete,
       input.token
-    ).pipe(map(versionInfo => versionInfo.map(info => info.id)))
+    ).pipe(
+      map(versionInfo => {
+        const numberVersionsToDelete =
+          versionInfo.length - input.minVersionsToKeep
+        return numberVersionsToDelete <= 0
+          ? []
+          : versionInfo.slice(0, numberVersionsToDelete).map(info => info.id)
+      })
+    )
   }
 
   return throwError(

src/input.ts

@@ -4,6 +4,7 @@ export interface InputParams {
   repo?: string
   packageName?: string
   numOldVersionsToDelete?: number
+  minVersionsToKeep?: number
   token?: string
 }
 
@@ -13,6 +14,7 @@ const defaultParams = {
   repo: '',
   packageName: '',
   numOldVersionsToDelete: 0,
+  minVersionsToKeep: 0,
   token: ''
 }
 
@@ -22,6 +24,7 @@ export class Input {
   repo: string
   packageName: string
   numOldVersionsToDelete: number
+  minVersionsToKeep: number
   token: string
 
   constructor(params?: InputParams) {
@@ -32,6 +35,7 @@ export class Input {
     this.repo = validatedParams.repo
     this.packageName = validatedParams.packageName
     this.numOldVersionsToDelete = validatedParams.numOldVersionsToDelete
+    this.minVersionsToKeep = validatedParams.minVersionsToKeep
     this.token = validatedParams.token
   }
 
@@ -41,6 +45,7 @@ export class Input {
       this.repo &&
       this.packageName &&
       this.numOldVersionsToDelete > 0 &&
+      this.minVersionsToKeep > 0 &&
       this.token
     )
   }

src/main.ts

@@ -14,6 +14,7 @@ function getActionInput(): Input {
     repo: getInput('repo') ? getInput('repo') : context.repo.repo,
     packageName: getInput('package-name'),
     numOldVersionsToDelete: Number(getInput('num-old-versions-to-delete')),
+    minVersionsToKeep: Number(getInput('min-versions-to-keep')),
     token: getInput('token')
   })
 }