function concat(arr1, arr2) { return [...arr1, ...arr2]; }Also consider tail, that takes an array or tuple, and returns all elements but the first.function tail(arg) { const [_, ...result] = arg; return result; }How would we type either of these in TypeScript?
让我们通过实际实现该函数并查看我们收到的错误来帮助一下: //not-assignable// ❌ 为什么这不起作用 😭functionadd(items:string|number[],newItem:string|number){returnitems.concat(newItem)} 显示以下错误: Type'string'isnot assignable to type'ConcatArray<number> & string'(2769)TypeScript playground...
It works when each argument isstring | string[]. It allows you to contextually check the type for each argument: if you doconst arr: string[] = [...multiple, ...array, ...stuff], you don't know which one is invalid if the assignment fails, but you do withArray<string>().conca...
开发者ID:our-city-app,项目名称:gae-plugin-framework,代码行数:7,代码来源:build.angular-json.ts 示例2: immutableMergeWithConcattingArrays ▲ exportfunctionimmutableMergeWithConcattingArrays(destObject: object, ...sources: object[]):object{constclonedDestObject = cloneDeep(destObject);returnmergeWith(c...
Arrays will not serve this purpose. TypeScript gives us a data type called tuple that helps to achieve such a purpose. It represents a heterogeneous collection of values. In other words, tuples enable storing multiple fields of different types. Tuples can also be passed as parameters to ...
--禁止不必要的字符串字面量或模板字面量的连接--> "no-useless-concat": 2, <!--禁用 void 操作符--> "no-void": 2, <!--禁止在注释中使用特定的警告术语--> "no-warning-comments": 2, <!--禁用 with 语句--> "no-with": 2, <!--强制在parseInt()使用基数参数--> "radix": 2, <...
🔗 Chapter 3 - Arrays, Tuples, Objects & Enums 🔗 Chapter 4 - Type Aliases, Literals, Functions & Never Type 🔗 Chapter 5 - Type Assertions & Type Casting 🔗 Chapter 6 - Classes & Interfaces 🔗 Chapter 7 - Index Signatures & keyof Assertions 🔗 Chapter 8 - Generics 🔗 Chap...
declare function addOrConcat(x: string): string; declare function addOrConcat(x: number): number; declare function addOrConcat(x: number | string): number | string; However, this is a little verbose and can be tedious to change in the future. Enter conditional types! declare function add...
应该使用 path.join 或 path.resolve 来代替 'no-path-concat': 2, // 禁止对函数的参数重新赋值 'no-param-reassign': 2, // 禁止 ++ 和 -- // @off 很常用 'no-plusplus': 0, // 禁止使用 process.env.NODE_ENV // @off 使用很常见 'no-process-env': 0, // 禁止使用 process.exit(0...
As with arrays, we can access the elements of tuples through subscripts: console.log(tupleType[0]); // semlinker console.log(tupleType[1]); // true When the tuple is initialized, if the type does not match, for example: tupleType = [true, "semlinker"];At this time, the TypeScript...