Asm-Dom – WebAssembly Virtual DOM

Re:Asm-Dom – WebAssembly Virtual DOM by crooked-v on Saturday May 20, 2017 @05:27PM (#14384435)

> Why the single quotes around function names?

Syntactically the same as not having them, aside from the fiddly details of string vs property name access to an object.

  thisObject = {
    usualPropertyName: value1,
    'property name with spaces': value2
  }

  thisObject.usualPropertyName
  thisObject['usualPropertyName'] // this works too
  thisObject['property name with spaces'] // you can't use the dot access style with this property name

> Why are some normal functions and others fat arrow functions?

Fat arrow functions bind "this" to whatever the surrounding context is, and if the only statement is a single object or value, it implicitly returns that.

That is to say, this:

   whatever => value

is syntactically the same as this:

   whatever => (
     value
   )

is syntactically the same as this:

  whatever => {
    return value
  }

> Why omit the parens around the param of a one parameter fat arrow function -- does that define a get accessor?

If there's only a single argument, you don't need the parentheses. This is meant mostly for the convenience of things like this:

  someArray.map(item => item.propertyName)

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Re:Asm-Dom – WebAssembly Virtual DOM by masklinn on Sunday May 21, 2017 @06:00AM (#14386543)

> Fat arrow functions bind "this" to whatever the surrounding context is

They don't actually bind `this` at all, there is a slot on the function object ([[ThisMode]] in the spec) which describes how to resolve `this` references for the function's body, for arrow function the mode is "lexical" and they simply grab the this reference from their lexical environment[0] as if it were any other non-local variable.

In fact, lexical resolution is the default, so what happens is during [[Call]][1] arrow functions will simply skip all the hard work in OrdinaryCallBindThis[2] by early-returning while the other two types (strict and global) have to resolve their thisValue then bind their local environment.

[0] https://www.ecma-international.org/ecma-262/6.0/#sec-lexical...

[1] https://www.ecma-international.org/ecma-262/6.0/#sec-ecmascr...

[2] https://www.ecma-international.org/ecma-262/6.0/#sec-ordinar...

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Re:Asm-Dom – WebAssembly Virtual DOM by mbasso on Sunday May 21, 2017 @06:06AM (#14386555)

Thank you for your answer. I just want to add a little thing to the first point.

> Why the single quotes around function names?

In this case I use quotes to prevent name mangling. I have to be sure that the uglify plugin in webpack does not mangle the names of that object because I'll call it from C++ in this way:

window['asmDomHelpers']['domApi']['createComment'](...)

Also, for the same reason, here I'm using this notation instead of this one:

window.asmDomHelpers.domApi.createComment(...)

to let know the closure compiler that I don't want name mangling.

Without quotes these two different compile processes might cause some problems

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