If you want to easily allow users to have your SPFx Web Part in a language of their liking, this guide is for you. To enable this multi language feature, we need

1. Define the keys and their types for localized strings in the mystrings.d.ts file like this:

declare interface ISvgToJsonWebPartStrings {
  saveConfiguration: string;
  libraryName: string;
  column: string;
  selectColumn: string;
}

declare module 'SvgToJsonWebPartStrings' {
  const strings: ISvgToJsonWebPartStrings;
  export = strings;
}

Depending on how much text you have in your Web Part, this can be a rather tedious task 😇.

(replace the SvgToJsonWebPartStrings with your Web Part Name)

2. Now in the en-us.js file (it’s in the loc folder) you will define for each of your keys that you have in the mystrings.d.ts file, a key-value pair in english. If you also need de-de.js for german, or fr-fr.js for french or any other language, create a file with the name of that locale in the loc folder and provide a translated version of the values of the en-us.js file (Hello 👋 Copilot).

This should look a bit like this:

define([], function() {
    return {
    "saveConfiguration": "Konfiguration speichern",
      "LibraryName": "Bibliotheksname",
      "column": "Spalte",
      "selectColumn": "Wählen Sie eine Spalte"
    }
});

3. Now replace all the hard coded strings like button texts, placeholders, labels, error messages etc. with strings.<keyname>, so for example strings.column.
4. As a last step, you need to import the strings into the file you want to use them with something like import * as strings from 'SvgToJsonWebPartStrings';

If you now run gulp build and gulp serve again to try out your masterpiece in te workbench and want to see your newly added languages, append the URL https://<your tenant>.sharepoint.com/_layouts/15/workbench.aspx with ?locale=de-de or any other locale that you created.

Congrats! You enabled a multi-language feature in your Web Part and also improved the logic of it. Now if you change a text, that will appear two or more times in your Web Part once it reflects this everywhere, so less manual changes!

If you want to have a look at the Web Part (which is still work in progress), you can do this here: react-svg-to-json-converter/. Let me know what you think!