Destructure / Easy Object Composition

[espruino-discuss]

Posted at 2021-01-30 by JosiahBryan

Hey guys!

It seems that destructuring assignment and composition is not supported in Espurino...is that true? Or is there a way to enable it? (Destruturing: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment)

For example, this doesn't work:

const someObject = { a: 1, b: 2 }
const { a, b } = someObject; // syntax errors on this line
const a = someObject.a; // ...but this does work

Similarly, this doesn't work:

const a = 1, b = 2;
const someObject = { a, b }; // syntax errors here
someObject.a = a; // ... but this works

Any plans to support these styles of operations?

[espruino-discuss]

Posted at 2021-01-30 by Robin

Sat 2021.01.30

Hi @josiahbryan,

'destructuring assignment and composition is not supported in Espurino'

That would be correct according to this reference beneath table ES6

http://www.espruino.com/Features

From the MDN link in post#1 > 'The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.'

Were you after the exact Destruturing syntax shown in post #1, or would a similar JSON object notation work for the task at hand?   ref: properties from objects

const someObject = { 'a': 1, 'b': 2 };
const a = someObject.a;
console.log ( "Value a: " + a );

// output
>Value a: 1

Note that use of dump() will show the same as:

const someObject = { a: 1, b: 2 };
const a = someObject.a;
console.log ( "Value a: " + a );

// output
>Value a: 1

> re: 'Any plans to support these styles of operations?'

We'll need to defer to @gfwilliams for the official plan. . . .

[gfwilliams]

Posted at 2021-02-01 by @gfwilliams

Yes, you're right - there's no support at the moment. Generally the state of language support is on the http://www.espruino.com/Features page as Robin says.

However nothing stops you from transpiling your JS code into something else. For instance if you go to Minification in settings and turn it to Closure (online) - Simple Optimisations you can then use destructuring.

There's a wishlist here which you can vote on: espruino/Espruino#1302

And generally I do try and add the most requested features when I get time :)