We just saw how to add values individually to maps. This can be tedious, however. For example, if we are working with a dataset that might be very large or unknown ahead of time, it would be nice to initialize a map with a function call rather than hundreds or thousands.
In this recipe, we'll take a look at how to create a new Map with the preexisting data.
This recipe assumes that you already have a workspace that allows you to create and run ES modules in your browser. If you don't, refer to the first two chapters.
- Open your command-line application and navigate to your workspace.
- Create a new folder named
11-05-create-map-from-data
. - Create a
main.js
file that defines a newclass
namedRocket
that takes a constructor argumentname
and assigns it to an instance property:
// main.js class Rocket { constructor(name) { this.name = name; } }
- Create an enum of various launch sites:
// main.js const LaunchSite = { ...