TypeScript Objects as Dictionary types as in C#

Question

I have some JavaScript code that uses objects as dictionaries; for example a \'person\' object will hold a some personal details keyed off the email address.

Answer 1

In newer versions of typescript you can use:

type Customers = Record

In older versions you can use:

var map: { [email: string]: Customer; } = { };
map['foo@gmail.com'] = new Customer(); // OK
map[14] = new Customer(); // Not OK, 14 is not a string
map['bar@hotmail.com'] = 'x'; // Not OK, 'x' is not a customer

You can also make an interface if you don't want to type that whole type annotation out every time:

interface StringToCustomerMap {
    [email: string]: Customer;
}

var map: StringToCustomerMap = { };
// Equivalent to first line of above