// 默认 function function_name(){} // 带返回值,:后的T为返回值类型 function function_name(): T{} // 带参函数,支持默认值 function function_name(param1[:type],param2[:type] = default_value) {} // 带剩余参数,函数的最后一个命名参数 restOfName 以 ... 为前缀,它将成为一个由剩余参数...
TypeScript can also infer the type from the default value.Named ParametersTyping named parameters follows the same pattern as typing normal parameters.Example function divide({ dividend, divisor }: { dividend: number, divisor: number }) { return dividend / divisor; } Try it Yourself » ...
exportdefaultfunctionsetupBasicContainer(options = {}){ options = defaults(options, {'orm-adapter:memory': MemoryAdapter,'serializer:application': FlatSerializer,'config:environment': {ormAdapter:'memory'} });letcontainer =newContainer(); forIn(options, (value, key) => { container.register(key,...
In this code, the SquareVal takes the return value from the function Square, which has a parameter type of interface SquareConfig, which has an optional value that can be assigned or not depending upon the situation of usage. The above code produces the following output. The way to write ...
// 声明函数返回值为voidfunctionwarnUser():void{console.log("This is my warning message");}=>tsc=>functionwarnUser(){console.log("This is my warning message");} 需要注意的是,声明一个 void 类型的变量没有什么作用,因为它的值只能为undefined或null: ...
interfaceAdmin{name:string;privileges:string[];}interfaceEmployee{name:string;startDate:Date;}type UnknownEmployee=Employee|Admin;functionprintEmployeeInformation(emp:UnknownEmployee){console.log("Name: "+emp.name);if("privileges"inemp){console.log("Privileges: "+emp.privileges);}if("startDate"inemp...
Make the months parameter optional but assign it a default value of 12 months if omitted. TypeScript Copy function loanCalculator (principle: number, interestRate: number, months = 12): string { let interest: number = interestRate / 1200; // Calculates the monthly interest rate let payment...
typing of a variable or function, TypeScript has the ability to infer types. You can create a function that simply returns a string. Knowing that, the compiler and tools provide type inference and automatically show the operations that can be performed on the return, as you can see inFigure...
yarn run v1.22.17$ babel src -d dist -x'.ts, .tsx'Successfullycompiled1filewithBabel(599ms).Donein4.05s. 可以看到项目dist目录下出现了编译好的js代码: "use strict";Object.defineProperty(exports,"__esModule", {value:true});exports.userToString=void0;varuserToString =functionuserToString(user...
TypeScript enforces the best practice of accessing internal fields (like id and fullName) through a reference to the class (this). Classes can also have constructor functions that include a feature C# has just adopted: automatic definition of fields. The constructor function in a TypeScript clas...