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  • Object arithmetic--operator alternative to Object.assign

Object arithmetic--operator alternative to Object.assign

# Bob Myers (10 years ago)

Apologies if something like this has already been proposed and/or rejected for whatever reason.

It would be nice to have an operator alternative for Object.assign. Perhaps "dot-plus' would work:

obj1 .+ {x, y}

To mutate an existing object, "dot-plus-equals":

obj1 .+= {x, y}

-- Bob

# Bergi (10 years ago)

Bob Myers schrieb:

Apologies if something like this has already been proposed and/or rejected for whatever reason.

I think you're looking for the same as strawman:define_properties_operator

It would be nice to have an operator alternative for Object.assign.

It uses an ":=" operator, so your example would read

obj1 := {x, y};

Bergi

# Allen Wirfs-Brock (10 years ago)

On Mar 11, 2015, at 7:23 AM, Bergi wrote:

Bob Myers schrieb:

Apologies if something like this has already been proposed and/or rejected for whatever reason.

I think you're looking for the same as strawman:define_properties_operator

also see: allenwb/ESideas/blob/master/dcltomethod.md

# Bob Myers (10 years ago)

Apologies if something like this has already been proposed.

We have simplified object literal syntax:

{a, b}

However, I often find myself writing this:

{a: x.a, b: y.b}

Would it be possible to have a syntax such as

{x.a, y.b}

Where the property name is taken from the last segment of the property reference, so that x.a becomes the value of property a?

-- Bob

# Tab Atkins Jr. (10 years ago)

On Tue, Mar 24, 2015 at 9:44 AM, Bob Myers <rtm at gol.com> wrote:

Apologies if something like this has already been proposed.

We have simplified object literal syntax:

{a, b}

However, I often find myself writing this:

{a: x.a, b: y.b}

Would it be possible to have a syntax such as

{x.a, y.b}

Where the property name is taken from the last segment of the property reference, so that x.a becomes the value of property a?

If you're taking both values from the same object, we have the syntax:

{a, b} = x;

This may or may not help you.

# Edwin Reynoso (10 years ago)

For different objects this is the only way I see possible with destructuring. IMO it's a bit ugly and weird to read deep destructuring:

let x = { a: 1 };
let y = { b: 2 };
let { x: { a }, y: { b } } = { x, y };

But I'd prefer Bob Myers's way:

let x = { a: 1 };
let y = { b: 2 };
{x.a, y.b}

Now that would be for destructuring. But isn't the following shorthand property assignment not destructuring:

var c = {x,y};

//so I'm thinking Bob wants the following:

var c = {x.a, b.y}; // {a: 1, b: 2}
# Rick Waldron (10 years ago)

On Tue, Mar 24, 2015 at 7:09 PM Edwin Reynoso <eorroe at gmail.com> wrote:

For different objects this is the only way I see possible with destructuring. IMO it's a bit ugly and weird to read deep destructuring:

let x = { a: 1 };
let y = { b: 2 };
let { x: { a }, y: { b } } = { x, y };

But I'd prefer Bob Myers's way:

let x = { a: 1 };
let y = { b: 2 };
{x.a, y.b}

Now that would be for destructuring. But isn't the following shorthand property assignment not destructuring:

var c = {x,y};

//so I'm thinking Bob wants the following:

var c = {x.a, b.y}; // {a: 1, b: 2}

As an exercise to see if this is reasonable, I spent some time drafting an outline addition to "12.2.5.9 Runtime Semantics: PropertyDefinitionEvaluation" that handled a newly defined (ie. thing I made up) "PropertyDefinition : IdentifierNameReference", but ran into issues when I had to consider all the forms that MemberExpression includes. people.mozilla.org/~jorendorff/es6-draft.html#sec

# Edwin Reynoso (10 years ago)

Yea, um I'm only 16 and been programming in Javascript for about 2-3 years. I haven't gotten to the Nitty Gritty part of Javascript specs. So I won't be able to help out with that. I was just throwing out what I mentioned above.