How do I interpolate variable values in the javascript or typescript string?

Question

Variables File:

export class VariableSettings {

   public static string_value: string = 'vikas/${id}/data';


}

Other File.

import {VariableSettings} from './variables';


    getData(id:string ){
      console.log(`${VariableSettings.string_value}`, `${id}`); 

      // it prints vikas/${id}/data abcd11123

    }`

Now I want the result like that "vikas/abcd11123/data". So how can I inject the id in that string.

Any suggestion regarding the same will be appreciated.

Thanks

Answer 1

To use interpolated strings you need to use the `` string separator as you do in your second snippet. If you already used a non interpolated string to hold the value of your setting, there is no way you can then interpolate it using the interpolation feature (you could use a regex to perform replacement but that is a bit messy).

The simplest solution is to make the field a function and have id as a parameter

export class VariableSettings {
    public static USER_BOOKINGS = (id: number) => `vikas/${id}/data`;
}
console.log(`${VariableSettings.USER_BOOKINGS(10)}`);
console.log(VariableSettings.USER_BOOKINGS(10)); // Or no interpolation at call site, not needed anymore if you just need the single value

The USER_BOOKINGS will now be a function that takes as arguments the parameters needed to construct the string. This way the parameters needed for the strings are clear and type-safe.