Fun with Stamps. Episode 24. New “name” feature

Hello. I’m developer Vasyl Boroviak and welcome to the twenty fourth episode of Vasyl Boroviak presents Fun with Stamps.

TL;DR: Now you can easily set MyStamp.name property like this:

const MyGateway = stampit({
  name: "SmsGateway"
})
MyGateway.name === "SmsGateway" // this used be hard to set

Available now in stampit@4.2.0 and @stamp/it@1.1.0. See docs at https://stampit.js.org

I find myself setting name of my stamps very often. Usually I use this package: https://www.npmjs.com/package/@stamp/named

import stampit from "@stamp/it"  // or "stampit"
import {setName} from "@stamp/named" // we will get rid of this line
import bunyan from "bunyan"
const HasLog = stampit({
  init(_, {stamp}) {
    // this will set logger name to "SmsGateway"
    this.log = bunyan.createLogger({name: stamp.name})
  }
})
const SmsGateway = stampit(HasLog, setName("SmsGateway"), {
  props: ...
  methods: ...
})

The code above adds HasLog behaviour which simply initialises a bunyan logger instance for each gateway instance. However, bunyan requires you to give it a name. So, I’m taking the logger name from the stamp’s name. In this case “SmsGateway”. I find this trick neat and concise. (Take that classic classes! You can’t do anything like that!)

Starting today no extra @stamp/named package needed! Just pass name: "StampName" to stampit.

import stampit from "@stamp/it"  // or "stampit"
import bunyan from "bunyan"
const HasLog = stampit({
  init(_, {stamp}) {
    // this will set logger name to "SmsGateway"
    this.log = bunyan.createLogger({name: stamp.name});
  }
})
const SmsGateway = stampit(HasLog, {
  name: "SmsGateway",
  props: ...
  methods: ...
})

Gotchas

• Won’t work in ES5 environments (like IE11). The name will always be “Stamp”. Name of a function can be set only in ≥ES6 environments.
• This code doesn’t work in JavaScript in general: SmsGateway.name = “bla”. Because Function.name is a special protected property.
• Composing with SmsGateway will inherit its name:

const TwillioGateway = SmsGateway.compose( ... )
TwillioGateway.name === "SmsGateway" // Oops!

or

const TwillioGateway = stampit({
    props: ...
    method: ...
    ...
  },
  SmsGateway // composing with a stamp which has a non-default name
)
TwillioGateway.name === "SmsGateway" // Oops!

You just need to overwrite it:

const TwillioGateway = SmsGateway.compose({
  name: "TwillioGateway",
  ... 
})

Have fun with stamps!

The rest of the episodes:

• Episode 1. Stamp basics
• Episode 2. Dependency injection in FP
• Episode 3. Comparing with the ES2015 classes
• Episode 4. Implementing stamps yourself in 30 LOC
• Episode 5. Composition design pattern
• Episode 6. Statics — properties on stamps
• Episode 7. Early and late dependency injection
• Episode 8. Tracking and overriding composition
• Episode 9. Detaching compose()
• Episode 10. My stamp mental model
• Episode 11. Interfering composition
• Episode 12. New @stamp home
• Episode 13. Method collision control
• Episode 14. New @stamp/it as a replacement of Stampit
• Episode 15. The @stamp/ modules ecosystem
• Episode 16. TypeScript mix-in classes vs Stamps
• Episode 17. Easy 100% unit test coverage in JS
• Episode 18. Dependency injection paradise
• Episode 19. Java/C# abstract methods in JavaScript
• Episode 20. Stampit v4
• Episode 21. Private data in JavaScript. 4 ways using stamps
• Episode 22. JavaScript instanceof as composable stamp
• Episode 23. New stampit.js.org with all the docs
• Episode 24. New “name” feature (this article)