TypeScript Unexpected token, A constructor, method, accessor or property was expected

问题

Just trying to write a function within a class using typescript.

class Test 
{
    function add(x: number, y: number): number {
        return x + y;
    }
}

This results in the following error:

TypeScript Unexpected token, A constructor, method, accessor or property was expected.

I copied the example from: https://www.typescriptlang.org/docs/handbook/functions.html

Am I missing something? I'm confused!

回答1:

You shouldn't use the function keyword in a Typescript class definition. Try this instead:

class Test { 
    add(x: number, y: number): number {
        return x + y;
    }
}

回答2:

TypeScript does not allow function declarations as class members; it has a slightly different syntax for that...

class Test 
{
    // This will bind the add method to Test.prototype
    add(x: number, y: number): number 
    {
        return x + y;
    }

    // This will create a closure based method within the Test class
    add2 = (x: number, y: number) => {
        return x + y;
    }
}

来源：https://stackoverflow.com/questions/43070702/typescript-unexpected-token-a-constructor-method-accessor-or-property-was-exp