Changed to function as documented. (#3596)

sampleSize.js

@@ -1,4 +1,5 @@
 import copyArray from './.internal/copyArray.js'
+import slice from './slice.js'
 
 /**
  * Gets `n` random elements at unique keys from `array` up to the
@@ -18,13 +19,14 @@ import copyArray from './.internal/copyArray.js'
  * // => [2, 3, 1]
  */
 function sampleSize(array, n) {
+  n = n == null ? 1 : n
   const length = array == null ? 0 : array.length
   if (!length || n < 1) {
     return []
   }
   n = n > length ? length : n
   let index = -1
-  const lastIndex = n - 1
+  const lastIndex = length - 1
   const result = copyArray(array)
   while (++index < n) {
     const rand = index + Math.floor(Math.random() * (lastIndex - index + 1))
@@ -32,7 +34,7 @@ function sampleSize(array, n) {
     result[rand] = result[index]
     result[index] = value
   }
-  return result
+  return slice(result, 0, n);
 }
 
 export default sampleSize