JavaScript join array into new array

Question

how do join the array and create new array?

var page_list = [ 'dkey', 'dvalue' ];
var json = '{"key1":"value1","key2":"value2","key3":"value3"}';
var jp = JSON.parse(json);

for( var index in jp ) {
   var obj = jp[index]; 
   //page_list.concat( ['test1','value2'] );
}

//expecting output
[ [ 'dkey', 'dvalue' ], [ 'key1', 'value1'], ['key2','value2'], ['key3','value3'] ]

https://jsfiddle.net/zerolfc/zjgx2pcj/1/

Can someone give me a solution, on how do I achieve the expecting output?

jp is not an array. jp is an object with attributes key1, key2 and key3. So jp[index] has no meaning. — Blip
– Blip, Commented Jun 19, 2015 at 11:18

Praveen Kumar Purushothaman · Accepted Answer · 2015-06-19 12:52:04Z

1

var page_list = [ 'dkey', 'dvalue' ];
var arr = []; //Create new array
arr.push(page_list); //Push page_list

var json = '{"key1":"value1","key2":"value2","key3":"value3"}';
var jp = JSON.parse(json);
for( var key in jp ) {
   arr.push([key, jp[key]]); //Push key, value 
}

document.write(JSON.stringify(arr))
//outputs
//[["dkey","dvalue"],["key1","value1"],["key2","value2"],["key3","value3"]]

edited Jun 19, 2015 at 12:52

Praveen Kumar Purushothaman

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answered Jun 19, 2015 at 11:18

Satpal

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Comments

Robins Gupta · Accepted Answer · 2015-06-19 11:24:38Z

1

You can do it like this:-

$(function() {

  var array = [];
  var page_list = [ 'dkey', 'dvalue' ];

  var new_arr = '{"key1":"value1","key2":"value2","key3":"value3"}';

  var jp = JSON.parse(new_arr);
  parentArr = [];

  for( var index in jp ) {
      var obj = jp[index];
      parentArr.push([index, obj]);
  }
  parentArr.push(page_list);
  console.log(parentArr);

 });

https://jsfiddle.net/zjgx2pcj/4/

answered Jun 19, 2015 at 11:24

Robins Gupta

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3 Comments

Cerbrus Over a year ago

Why did you add $(function(){ }); ?

Robins Gupta Over a year ago

@Cerbrus Just defining it all in a scope. Its not necessary you can remove it .

Cerbrus Over a year ago

For answers on SO, I'd advice against adding extra's like that.

Cerbrus · Accepted Answer · 2015-06-19 11:28:25Z

1

You can do this:

var page_list = [ 'dkey', 'dvalue' ];
var json = '{"key1":"value1","key2":"value2","key3":"value3"}';
var jp = JSON.parse(json);

// Map all values from `jp` into an array.
var arr = Object.keys(jp).map(function (key) {return [key, jp[key]]});
// Add `page_list` as first item of the array.
arr.unshift(page_list);

console.log(arr);
alert(JSON.stringify(arr));

Object.keys(jp) gets an array of keys from jp (So, ['key1', 'key2', 'key3']).

Then, .map iterates over that result, where [key, jp[key] is returned for each key, which results in ['key1', 'value1'] etc.
Finally, page_list is added at the front of arr.

edited Jun 19, 2015 at 11:28

answered Jun 19, 2015 at 11:21

Cerbrus

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Comments

Cerbrus · Accepted Answer · 2015-06-19 12:54:22Z

1

Use .push() and remove the obj:

$(function() {
    var array = [];
    var page_list = [ 'dkey', 'dvalue' ];
    var new_arr = '{"key1":"value1","key2":"value2","key3":"value3"}';

    var jp = JSON.parse(new_arr);
    array.push( page_list );
    for( var index in jp ) {
        array.push( [index, jp[index]] );
    }
    console.log ( array );
});

Fiddle: https://jsfiddle.net/praveenscience/zjgx2pcj/6/

edited Jun 19, 2015 at 12:54

Cerbrus

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answered Jun 19, 2015 at 11:17

Praveen Kumar Purushothaman

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3 Comments

Satpal Over a year ago

Doesn't outputs the expected result.

Satpal Over a year ago

var arr = []; arr.push(page_list); Repeating the comment Doesn't outputs the expected result

Satpal Over a year ago

Yes it looks good now you accept my original comment Doesn't outputs the expected result

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