fix(front, back) -> undefined exception; feat(resize)

test/List.test.js

@@ -49,7 +49,7 @@ test('move, empty', () => {
 
 test('constructor, assign', () => {
   expect(new List().size()).toEqual(0)
-  expect(new List().back).toEqual(undefined)
+  expect(() => new List().back).toThrow()
   expect(listEquArray(new List(null), [null])).toBeTruthy()
   expect(listEquArray(new List(null, 2), [null, null])).toBeTruthy()
   {
@@ -60,6 +60,19 @@ test('constructor, assign', () => {
   }
 })
 
+test('resize', () => {
+  {
+    const list = List.from([1, 2, 3])
+    list.resize(1)
+    expect(listEquArray(list, [1])).toBeTruthy()
+  }
+  {
+    const list = List.from([1])
+    list.resize(3, 2)
+    expect(listEquArray(list, [1, 2, 2])).toBeTruthy()
+  }
+})
+
 test('insert, clone', () => {
   {
     const list = List.from([1, 2])
@@ -135,4 +148,4 @@ test('pushBack, pushFront, popBack, popFront, back, front', () => {
 test('toJSON, toString', () => {
   expect(List.from([1, 2]).toJSON()).toEqual('[ 1, 2 ]')
   expect(List.from([0n]).toString()).toEqual('[ 0 ]')
-})
+})