Javascript get all value of keys in array?

Question

How can I get all values of keys in an array without jQuery?

var species = [{"code_name":"b","public_name":"a"},{"code_name":"d","public_name":"c"},{"code_name":"f","public_name":"e"}];

var speciesVals = Object.keys(species).map(function (val, key) {
    return val;
});

Result:

[ '0',
  '1',
  '2',
  '_atomics',
  '_parent',
  '_cast',
  '_markModified',
  '_registerAtomic',
  '$__getAtomics',
  'hasAtomics',
  '_mapCast',
  'push',
  'nonAtomicPush',
  '$pop',
  'pop',
  '$shift',
  'shift',
  'pull',
  'splice',
  'unshift',
  'sort',
  'addToSet',
  'set',
  'toObject',
  'inspect',
  'indexOf',
  'remove',
  '_path',
  'isMongooseArray',
  'validators',
  '_schema' ]

But I am after:

["code_name":["b", "d", "d"], "public_name":["a", "c", "e"]

Is it possible?

EDIT:

What about this:

[{"code_name":["b", "d", "d"]}, {"public_name":["a", "c", "e"}]

Why not just use a loop? for( var result = {}, i=0, l=species.length, k; i<l; i++) { for( k in species[i]) if( species[i].hasOwnProperty(k)) { result[k] = result[k] || []; result[k].push(species[i][k]); }} — Niet the Dark Absol
– Niet the Dark Absol, Commented Jul 25, 2016 at 9:32

Pranav C Balan · Accepted Answer · 2016-07-25 12:28:22Z

3

Use JavaScript Array#reduce method.

var species = [{
  "code_name": "b",
  "public_name": "a"
}, {
  "code_name": "d",
  "public_name": "c"
}, {
  "code_name": "f",
  "public_name": "e"
}];

var temp = species.reduce(function(res, v) {
  // iterate over object(array element)
  Object.keys(v).forEach(function(k) {
    // define property as array if not defined
    res[k] = res[k] || [];
    // push the value to prefered array
    res[k].push(v[k]);
  });
  // return the updated object
  return res;
  // define the initial value as object to hold the result
}, {});

// now create your expected result
var speciesVals = Object.keys(temp) // get all property names
  .map(function(v) { //iterate over them to generate the result array
    var obj = {}; // create object for 
    obj[v] = temp[v]; // add property
    return obj; // return object (which is the new array element)
  });


console.log(speciesVals);

edited Jul 25, 2016 at 12:28

answered Jul 25, 2016 at 9:34

Pranav C Balan

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2 Comments

Run Over a year ago

thanks. what about this: [{"code_name":["b", "d", "d"]}, {"public_name":["a", "c", "e"}] ?

Pranav C Balan Over a year ago

@teelou : glad to help you :)

Shomz · Accepted Answer · 2016-07-25 11:52:36Z

1

Sure it's possible. If your object keys are the same for every object in the array, you can do:

var species = [{"code_name":"b","public_name":"a"},{"code_name":"d","public_name":"c"},{"code_name":"f","public_name":"e"}];
var res = {code_name: [], public_name: []};
   
for(var i = 0; i < species.length; i++){
    res.code_name.push(species[i].code_name);
    res.public_name.push(species[i].public_name);
}

console.log(res);

EDIT

To get an array of objects:

var species = [{"code_name":"b","public_name":"a"},{"code_name":"d","public_name":"c"},{"code_name":"f","public_name":"e"}];
var res = [{code_name: []}, {public_name: []}];
   
for(var i = 0; i < species.length; i++){
    res[0].code_name.push(species[i].code_name);
    res[1].public_name.push(species[i].public_name);
}

console.log(res);

edited Jul 25, 2016 at 11:52

answered Jul 25, 2016 at 9:35

Shomz

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5 Comments

Shomz Over a year ago

You're welcome! Yeah, no need to overcomplicate because this is a simple old-school iteration task. :)

Run Over a year ago

i totally agree with u. was overthinking to .prototype side!

Shomz Over a year ago

That makes sense if you plan to do many variations of this (like fetching different keys, using different original array structure, different organization of results, etc.), but if you want a code that solves this single task efficiently, I'd go with a single loop every time.

Run Over a year ago

cool. thanks for the tip. Btw, how can I make this instead [{"code_name":["b", "d", "d"]}, {"public_name":["a", "c", "e"}] - objects in an array?

Shomz Over a year ago

No problem, I'm glad I could help.

Nina Scholz · Accepted Answer · 2016-07-25 09:37:07Z

1

I suggest to use a fixed array for the properties, because you need only 'code_name and public_name.

var species = [{ "code_name": "b", "public_name": "a" }, { "code_name": "d", "public_name": "c" }, { "code_name": "f", "public_name": "e" }],
    speciesVals = {};

species.forEach(function (a) {
    ['code_name', 'public_name'].forEach(function (k) {
        speciesVals[k] = speciesVals[k] || [];
        speciesVals[k].push(a[k]);
    });
});

console.log(speciesVals);

answered Jul 25, 2016 at 9:37

Nina Scholz

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