Can one set multiple properties inside an object literal to the same value?

Question

For example, can I do this?:

{ 
   a: b: c: d: 1,
   e: 2,
   geh: function() { alert("Hi!") }
}

EDIT: Is there some way I can avoid doing this?:

{ 
   a: 1,
   b: 1,
   c: 1,
   d: 1,
   e: 2,
   geh: function() { alert("Hi!") }
}

Answer 1

An update to this (in terms of the latest JavaScript abilities) avoiding unwanted defined vars:

{   let v;   var obj = {      "a": (v = 'some value'),      "b": v,      "c": v   }; } 

This will mean v won't be defined outside the block, but obj will be.

Original answer

Another way of doing the same thing is:

var v; var obj = {      "a": (v = 'some value'),      "b": v,      "c": v }; 

Answer 2

You could set a line of equality between various properties:

var foo = {};
foo.a = foo.b = foo.c = "Hello";

Or you could just create a method that does the mass-assignment for you:

var foo = {
    setValue: function( props, value ) {
        while ( props.length ) this[ props.pop() ] = value;
    }
}

foo.setValue( [ "a", "b", "c" ] , "Foo" );

Answer 3

You could try this. It's not the syntactic sugar you're looking for (eg. {a,b,c:1, d:2}) but it's another way to do it, although all of these answers are pretty much fine.

(object,fields,value)=>Object.assign(object||{}, ...fields.map(f=>({[f]:value}) ))

Explanation:

(object,fields,value)=>

Takes an object (or falsey value if you want a new object, feel free to rearrange the argument order)

Object.assign(object||{},

Will return an object based on object and it will mutate the object. To disable this, simply add a first argument object literal like this Object.assign({}, object || {}, ...

...fields.map(f=>({[f]:value}) )

Will spread the array of fields mapped to objects as a list of extra arguments to Object.assign. ['a','b'].map(f=>({[f]:value}) ) will give [{a:value}, {b:value}] and f(...[{a:1},{b:1}]) is like f({a:1},{b:1}). Object.assign does the rest :)