diff --git a/codes/javascript/chapter_computational_complexity/time_complexity.js b/codes/javascript/chapter_computational_complexity/time_complexity.js
index a25811198..22d52e333 100644
--- a/codes/javascript/chapter_computational_complexity/time_complexity.js
+++ b/codes/javascript/chapter_computational_complexity/time_complexity.js
@@ -120,7 +120,6 @@ function factorialRecur(n) {
     return count
 }
 
-
 /* 生成一个数组，元素为 { 1, 2, ..., n }，顺序被打乱 */
 function randomNumbers(n) {
     // 生成数组 nums = { 1, 2, 3, ..., n }
diff --git a/codes/typescript/chapter_computational_complexity/time_complexity.ts b/codes/typescript/chapter_computational_complexity/time_complexity.ts
index 8243d4ee8..25520ec79 100644
--- a/codes/typescript/chapter_computational_complexity/time_complexity.ts
+++ b/codes/typescript/chapter_computational_complexity/time_complexity.ts
@@ -22,7 +22,7 @@ function linear(n: number): number {
 }
 
 /* 线性阶（遍历数组） */
-function arrayTraversal(nums: number[]) {
+function arrayTraversal(nums: number[]): number {
     let count = 0
     // 循环次数与数组长度成正比
     for (let num of nums) {
@@ -32,7 +32,7 @@ function arrayTraversal(nums: number[]) {
 }
 
 /* 平方阶 */
-function quadratic(n: number) {
+function quadratic(n: number): number {
     let count = 0
     // 循环次数与数组长度成平方关系
     for (let i = 0; i < n; i++) {
@@ -44,7 +44,7 @@ function quadratic(n: number) {
 }
 
 /* 平方阶（冒泡排序） */
-function bubbleSort(nums: number[]) {
+function bubbleSort(nums: number[]): number {
     let count = 0 // 计数器
     // 外循环：待排序元素数量为 n-1, n-2, ..., 1
     for (let i = nums.length - 1; i > 0; i--) {
@@ -63,7 +63,7 @@ function bubbleSort(nums: number[]) {
 }
 
 /* 指数阶（循环实现） */
-function exponential(n: number) {
+function exponential(n: number): number {
     let count = 0,
         base = 1
     // cell 每轮一分为二，形成数列 1, 2, 4, 8, ..., 2^(n-1)
@@ -78,13 +78,13 @@ function exponential(n: number) {
 }
 
 /* 指数阶（递归实现）*/
-function expRecur(n: number) {
+function expRecur(n: number): number {
     if (n == 1) return 1
     return expRecur(n - 1) + expRecur(n - 1) + 1
 }
 
 /* 对数阶（循环实现） */
-function logarithmic(n: number) {
+function logarithmic(n: number): number {
     let count = 0
     while (n > 1) {
         n = n / 2
@@ -94,13 +94,13 @@ function logarithmic(n: number) {
 }
 
 /* 对数阶（递归实现）*/
-function logRecur(n: number) {
+function logRecur(n: number): number {
     if (n <= 1) return 0
     return logRecur(n / 2) + 1
 }
 
 /* 线性对数阶 */
-function linearLogRecur(n: number) {
+function linearLogRecur(n: number): number {
     if (n <= 1) return 1
     let count = linearLogRecur(n / 2) + linearLogRecur(n / 2)
     for (let i = 0; i < n; i++) {
@@ -110,7 +110,7 @@ function linearLogRecur(n: number) {
 }
 
 /* 阶乘阶（递归实现） */
-function factorialRecur(n: number) {
+function factorialRecur(n: number): number {
     if (n == 0) return 1
     let count = 0
     // 从 1 个分裂出 n 个
diff --git a/docs/chapter_computational_complexity/time_complexity.md b/docs/chapter_computational_complexity/time_complexity.md
index aca04222e..356a3b418 100644
--- a/docs/chapter_computational_complexity/time_complexity.md
+++ b/docs/chapter_computational_complexity/time_complexity.md
@@ -857,7 +857,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 线性阶（遍历数组） */
-    function arrayTraversal(nums: number[]) {
+    function arrayTraversal(nums: number[]): number {
         let count = 0
         // 循环次数与数组长度成正比
         for (let num of nums) {
@@ -964,7 +964,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 平方阶 */
-    function quadratic(n: number) {
+    function quadratic(n: number): number {
         let count = 0
         // 循环次数与数组长度成平方关系
         for (let i = 0; i < n; i++) {
@@ -1113,7 +1113,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 平方阶（冒泡排序） */
-    function bubbleSort(nums: number[]) {
+    function bubbleSort(nums: number[]): number {
       let count = 0 // 计数器
       // 外循环：待排序元素数量为 n-1, n-2, ..., 1
       for (let i = nums.length - 1; i > 0; i--) {
@@ -1225,7 +1225,7 @@ $$
 
     ```js title="time_complexity.js"
     /* 指数阶（循环实现） */
-    function exponential(n) {
+    function exponential(n): number {
         let count = 0,
             base = 1
         // cell 每轮一分为二，形成数列 1, 2, 4, 8, ..., 2^(n-1)
@@ -1244,7 +1244,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 指数阶（循环实现） */
-    function exponential(n: number) {
+    function exponential(n: number): number {
         let count = 0,
             base = 1
         // cell 每轮一分为二，形成数列 1, 2, 4, 8, ..., 2^(n-1)
@@ -1332,7 +1332,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 指数阶（递归实现）*/
-    function expRecur(n: number) {
+    function expRecur(n: number): number {
         if (n == 1) return 1
         return expRecur(n - 1) + expRecur(n - 1) + 1
     }
@@ -1430,7 +1430,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 对数阶（循环实现） */
-    function logarithmic(n: number) {
+    function logarithmic(n: number): number {
         let count = 0
         while (n > 1) {
             n = n / 2
@@ -1513,7 +1513,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 对数阶（递归实现）*/
-    function logRecur(n: number) {
+    function logRecur(n: number): number {
         if (n <= 1) return 0
         return logRecur(n / 2) + 1
     }
@@ -1615,7 +1615,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 线性对数阶 */
-    function linearLogRecur(n: number) {
+    function linearLogRecur(n: number): number {
         if (n <= 1) return 1
         let count = linearLogRecur(n / 2) + linearLogRecur(n / 2)
         for (let i = 0; i < n; i++) {
@@ -1730,7 +1730,7 @@ $$
 
     ```typescript title="time_complexity.ts"
     /* 阶乘阶（递归实现） */
-    function factorialRecur(n: number) {
+    function factorialRecur(n: number): number {
         if (n == 0) return 1
         let count = 0
         // 从 1 个分裂出 n 个