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is there a function enumerating all element in an object?

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  is there a function enumerating all element in an object? Stone Zhong <stone.zhong@gmail.com> - 2015-08-21 22:44 -0700
    Re: is there a function enumerating all element in an object? nathank887@gmail.com - 2015-10-28 22:11 -0700
      Re: is there a function enumerating all element in an object? Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-10-29 15:59 -0200
        Re: is there a function enumerating all element in an object? Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-10-29 16:20 -0200
          Re: is there a function enumerating all element in an object? "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-10-29 20:58 +0100
            Re: is there a function enumerating all element in an object? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-29 20:49 +0000
              Re: is there a function enumerating all element in an object? "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-10-29 22:49 +0100
                Re: is there a function enumerating all element in an object? Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-10-30 16:05 -0200
                Re: is there a function enumerating all element in an object? RobG <rgqld@iinet.net.au> - 2015-11-14 13:16 -0800
                  Re: is there a function enumerating all element in an object? Chuck Anderson <seemysig@thisis.invalid> - 2015-11-14 17:58 -0700
                  Re: is there a function enumerating all element in an object? Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-11-16 14:26 -0200
    Re: is there a function enumerating all element in an object? donmaximo01@gmail.com - 2015-10-29 06:08 -0700

#28553 — is there a function enumerating all element in an object?

Hi there,

Is there a member function in ES5 or ES6 doing something like below? I saw a repeated pattern of such code, especially if you use reactjs

var forEachItemInObject = function(obj, callback) {
  var ret = [ ];
  for (var key in obj) {
    ret.push(callback(key, obj[key]));
  }
  return ret;
};

Thanks,
Stone

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#28858

On Saturday, August 22, 2015 at 12:44:51 AM UTC-5, Stone Zhong wrote:
> Hi there,
> 
> Is there a member function in ES5 or ES6 doing something like below? I saw a repeated pattern of such code, especially if you use reactjs
> 
> var forEachItemInObject = function(obj, callback) {
>   var ret = [ ];
>   for (var key in obj) {
>     ret.push(callback(key, obj[key]));
>   }
>   return ret;
> };
> 
> Thanks,
> Stone

Use Object.keys(objectName) to get an array of keys, then you can use forEach(). For example, this alerts each key in myObject:


Object.keys(myObject).forEach(function(key){
    alert(key);
});


See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach

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#28860

nathank887@gmail.com wrote:
> Stone Zhong wrote:
>> Is there a member function in ES5 or ES6 doing something like below? I saw a repeated pattern of such code, especially if you use reactjs
>>
>> var forEachItemInObject = function(obj, callback) {
>>   var ret = [ ];
>>   for (var key in obj) {
>>     ret.push(callback(key, obj[key]));
>>   }
>>   return ret;
>> };
>>

> 
> Use Object.keys(objectName) to get an array of keys, then you can use forEach(). For example, this alerts each key in myObject:
> 
> 
> Object.keys(myObject).forEach(function(key){
>     alert(key);
> });
> 

In ES2015 (ES6), the OP's code might be:

Object.keys(obj).map(key => callback(key, obj[key]));


-- 
Joao Rodrigues

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#28861

On 29-10-2015 15:59, Joao Rodrigues wrote:
> nathank887@gmail.com wrote:
>> Stone Zhong wrote:
>>> Is there a member function in ES5 or ES6 doing something like below? I saw a repeated pattern of such code, especially if you use reactjs
>>>
>>> var forEachItemInObject = function(obj, callback) {
>>>   var ret = [ ];
>>>   for (var key in obj) {
>>>     ret.push(callback(key, obj[key]));
>>>   }
>>>   return ret;
>>> };

> 
> In ES2015 (ES6), the OP's code might be:
> 
> Object.keys(obj).map(key => callback(key, obj[key]));
> 
> 

Or:

Array.from(Object.keys(obj), key => callback(key, obj[key]));

-- 
Joao Rodrigues

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#28862

Joao Rodrigues <groups_jr-1@yahoo.com.br> wrote on 29 Oct 2015 in 
comp.lang.javascript:

>> Object.keys(obj).map(key => callback(key, obj[key]));
> Or:
> 
> Array.from(Object.keys(obj), key => callback(key, obj[key]));

Could you please explain to us simple minded how this realy works?



-- 
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

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#28863

"Evertjan." <exxjxw.hannivoort@inter.nl.net> writes:

> Joao Rodrigues <groups_jr-1@yahoo.com.br> wrote on 29 Oct 2015 in 
> comp.lang.javascript:
>
>>> Object.keys(obj).map(key => callback(key, obj[key]));
>> Or:
>> 
>> Array.from(Object.keys(obj), key => callback(key, obj[key]));
>
> Could you please explain to us simple minded how this realy works?

In ES6, the form

  x => expression

is similar to

  function (x) { return expression; }

There are a few differences ("this" is lexical in an arrow function and
there is no "arguments" object) but neither of those matter here I don't
think.

[You may have multiple parameters:

  (a, b) => a + b

and you may have an explicit block rather than a single expression:

  x => { console.log(`x = ${x}`); return x; }

which sneaks in another ES6 feature: template strings.]

-- 
Ben.

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#28864

Ben Bacarisse <ben.usenet@bsb.me.uk> wrote on 29 Oct 2015 in 
comp.lang.javascript:

> "Evertjan." <exxjxw.hannivoort@inter.nl.net> writes:
> 
>> Joao Rodrigues <groups_jr-1@yahoo.com.br> wrote on 29 Oct 2015 in 
>> comp.lang.javascript:
>>
>>>> Object.keys(obj).map(key => callback(key, obj[key]));
>>> Or:
>>> 
>>> Array.from(Object.keys(obj), key => callback(key, obj[key]));
>>
>> Could you please explain to us simple minded how this realy works?
> 
> In ES6, the form
> 
>   x => expression
> 
> is similar to
> 
>   function (x) { return expression; }
> 
> There are a few differences ("this" is lexical in an arrow function and
> there is no "arguments" object) but neither of those matter here I don't
> think.
> 
> [You may have multiple parameters:
> 
>   (a, b) => a + b
> 
> and you may have an explicit block rather than a single expression:
> 
>   x => { console.log(`x = ${x}`); return x; }
> 
> which sneaks in another ES6 feature: template strings.]

Thank you, now I know the name, I will start here:

<https://developer.mozilla.org/en-
US/docs/Web/JavaScript/Reference/Functions/Arrow_functions#Browser_compatibi
lity> 



-- 
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

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#28865

Evertjan wrote:
> Ben Bacarisse wrote:
> 
>> "Evertjan." <exxjxw.hannivoort@inter.nl.net> writes:
>>
>>> Joao Rodrigues wrote:
>>>
>>>>> Object.keys(obj).map(key => callback(key, obj[key]));
>>>> Or:
>>>>
>>>> Array.from(Object.keys(obj), key => callback(key, obj[key]));
>>>
>>> Could you please explain to us simple minded how this realy works?
>>
>> In ES6, the form
>>
>>   x => expression
>>
>> is similar to
>>
>>   function (x) { return expression; }
>> [snip]

> Thank you, now I know the name, I will start here:
> 
> <https://developer.mozilla.org/en-
> US/docs/Web/JavaScript/Reference/Functions/Arrow_functions#Browser_compatibi
> lity> 

I hope this article will help you get started using ES2015 (6th edition):
<http://www.smashingmagazine.com/2015/10/es6-whats-new-next-version-javascript/>

-- 
Joao Rodrigues

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#28887

On Friday, October 30, 2015 at 7:49:49 AM UTC+10, Evertjan. wrote:
> Ben Bacarisse <ben.usenet@bsb.me.uk> wrote on 29 Oct 2015 in 
> comp.lang.javascript:
> 
> > "Evertjan." <exxjxw.hannivoort@inter.nl.net> writes:
> > 
> >> Joao Rodrigues <groups_jr-1@yahoo.com.br> wrote on 29 Oct 2015 in 
> >> comp.lang.javascript:
> >>
> >>>> Object.keys(obj).map(key => callback(key, obj[key]));
> >>> Or:
> >>> 
> >>> Array.from(Object.keys(obj), key => callback(key, obj[key]));
> >>
> >> Could you please explain to us simple minded how this realy works?
[...]
> 
> Thank you, now I know the name, I will start here:
> 
> <https://developer.mozilla.org/en-
> US/docs/Web/JavaScript/Reference/Functions/Arrow_functions#Browser_compatibi
> lity> 

There is always the ECMAScript 2015 specification[1], but it's impossibly turgid in many places. MDN is becoming an increasingly important resource.

1. <http://ecma-international.org/ecma-262/6.0/index.html#sec-arrow-function-definitions>

-- 
Rob 

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#28888

RobG wrote:
> On Friday, October 30, 2015 at 7:49:49 AM UTC+10, Evertjan. wrote:
>> Ben Bacarisse <ben.usenet@bsb.me.uk> wrote on 29 Oct 2015 in 
>> comp.lang.javascript:
>>
>>> "Evertjan." <exxjxw.hannivoort@inter.nl.net> writes:
>>>
>>>> Joao Rodrigues <groups_jr-1@yahoo.com.br> wrote on 29 Oct 2015 in 
>>>> comp.lang.javascript:
>>>>
>>>>>> Object.keys(obj).map(key => callback(key, obj[key]));
>>>>> Or:
>>>>>
>>>>> Array.from(Object.keys(obj), key => callback(key, obj[key]));
>>>> Could you please explain to us simple minded how this realy works?
> [...]
>> Thank you, now I know the name, I will start here:
>>
>> <https://developer.mozilla.org/en-
>> US/docs/Web/JavaScript/Reference/Functions/Arrow_functions#Browser_compatibi
>> lity> 
> 
> There is always the ECMAScript 2015 specification[1], but it's impossibly turgid in many places. MDN is becoming an increasingly important resource.
> 
> 1. <http://ecma-international.org/ecma-262/6.0/index.html#sec-arrow-function-definitions>
> 

Probably steppin' in a pile of poo here (long time lurker and c.lang.php 
participant), but I only recently learned of Object.toSource, which 
displays the source code of an object - in Firefox.

The Mozilla developers site warns that it should not be used on an 
active site as there are many incompatibilities (like no one else 
supports it?), but I have used it in the manner they suggest.  It is 
very handy while debugging - within Firefox.

-- 
  *****************************
   Chuck Anderson • Boulder, CO
   http://cycletourist.com
   Turn Off, Tune Out, Drop In
  *****************************

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#28893

Em 14/11/2015 19:16, RobG escreveu:
> On Friday, October 30, 2015 at 7:49:49 AM UTC+10, Evertjan. wrote:
>>
>> Thank you, now I know the name, I will start here:
>>
>> <https://developer.mozilla.org/en-
>> US/docs/Web/JavaScript/Reference/Functions/Arrow_functions#Browser_compatibi
>> lity> 
> 
> There is always the ECMAScript 2015 specification[1], but it's impossibly turgid in many places. MDN is becoming an increasingly important resource.
> 
> 1. <http://ecma-international.org/ecma-262/6.0/index.html#sec-arrow-function-definitions>
> 

The ECMAScript specification is now developed on GitHub, instead of a
Word document:
<https://github.com/tc39/ecma262/releases/tag/es2016-draft-1>

The pdf version of the ES2015 specification contains 545 pages! FTR,
Golang specification is far shorter than that.

-- 
Joao Rodrigues

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#28859

FOR My Price and Pictures On the Pills / vals contact me at 

zita3322@gmail.com

waiting 

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