That ‘nameIs’ function is wild.
Anthony Good

When you create a method using ES6 method shorthand, the runtime will set the generated function’s name from the property’s name.

const key = 'hello'
const obj = {
[key] () {
throw new Error('ヤバい!!')
const fn = obj[key]
// => 'hello'

(This behavior is defined in ES2015 Specification §14.3.9.)

This means when the function throws an error, the stack trace should include the function name hello in the stack trace:

Uncaught Error: ヤバい!!
at hello (<anonymous>:4:11)
at <anonymous>:1:1

This is how we create a named function with a dynamic name.

Unfortunately, Firefox does not respect this name when generating the stack trace… It only works in V8 (Chrome and Node).

So, the 名は function takes a name , a function f, and returns a named function that just forwards the arguments to f.

Hope this helps!