TypeScript 基础
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类型注解：为变量、函数参数和返回值指定类型。
typescript复制代码let count: number = 10;function greet(name: string): string {return `Hello, ${name}!`; } -
接口和类型别名：定义对象结构和复杂类型。
typescript复制代码interface User {id: number;name: string; }type ID = number | string; -
泛型：创建可重用的组件。
typescript复制代码function identity<T>(arg: T): T {return arg; }let output = identity<string>("Hello"); -
类和接口：面向对象编程。
typescript复制代码class Animal {name: string;constructor(name: string) {this.name = name;}move(distance: number = 0) {console.log(`${this.name} moved ${distance}m.`);} }interface Flying {fly(distance: number): void; }class Bird extends Animal implements Flying {fly(distance: number) {console.log(`${this.name} flew ${distance}m.`);} }
算法准备：数组扁平化
数组扁平化是指将多维数组转换为一维数组。以下是几种实现方式：
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使用递归：
typescript复制代码function flattenArray(arr: any[]): any[] {let result: any[] = [];for (let item of arr) {if (Array.isArray(item)) {result = result.concat(flattenArray(item));} else {result.push(item);}}return result; }console.log(flattenArray([1, [2, [3, 4]], 5])); // [1, 2, 3, 4, 5] -
使用
reduce和递归：typescript复制代码function flattenArray(arr: any[]): any[] {return arr.reduce((acc, val) => Array.isArray(val) ? acc.concat(flattenArray(val)) : acc.concat(val), []); }console.log(flattenArray([1, [2, [3, 4]], 5])); // [1, 2, 3, 4, 5] -
使用栈：
typescript复制代码function flattenArray(arr: any[]): any[] {const stack = [...arr];const result: any[] = [];while (stack.length) {const next = stack.pop();if (Array.isArray(next)) {stack.push(...next);} else {result.push(next);}}return result.reverse(); }console.log(flattenArray([1, [2, [3, 4]], 5])); // [1, 2, 3, 4, 5]
算法题：两个有序数组合并成一个有序数组
合并两个有序数组并保持有序，可以使用双指针法。
typescript复制代码function mergeSortedArrays(arr1: number[], arr2: number[]): number[] {let i = 0, j = 0;const result: number[] = [];while (i < arr1.length && j < arr2.length) {if (arr1[i] < arr2[j]) {result.push(arr1[i]);i++;} else {result.push(arr2[j]);j++;}}// 处理剩余元素while (i < arr1.length) {result.push(arr1[i]);i++;}while (j < arr2.length) {result.push(arr2[j]);j++;}return result;
}// 测试
const arr1 = [1, 3, 5, 7];
const arr2 = [2, 4, 6, 8];
console.log(mergeSortedArrays(arr1, arr2)); // [1, 2, 3, 4, 5, 6, 7, 8]