array.push(object) not pushed at the end of the loop in javascript

Question

var temparray1 = [[1,3,4],[5,6,7],[8,9,10]];
var final = [];
var obj = {};
for(var temp in temparray1){
    for(var test in temparray1[temp]){
        obj.b = temparray1[temp][0];
        obj.c = temparray1[temp][1];
        obj.d = temparray1[temp][2];
    }
    console.log(obj);
    final.push(obj);
}

current output

[{ b: 8, c: 9, d: 10 }
{ b: 8, c: 9, d: 10 }
{ b: 8, c: 9, d: 10 }]

expected Out put:

[{ b: 1, c: 3, d: 4 }
{ b: 5, c: 6, d: 7 }
{ b: 8, c: 9, d: 10 }]

i am running my javascript in node.js -v 8.1.x server

in the console at the end of the for loop it prints the required out put but not in the array push

Never use for ..in loops to iterate over arrays, and obj isn't defined in your code ? — adeneo
– adeneo, Commented Aug 8, 2017 at 16:09
yes obj = {} already declared but may i know why for ..in is not possible it is the normal iteration i think — muthukumar selvaraj
– muthukumar selvaraj, Commented Aug 9, 2017 at 8:50

Erazihel · Accepted Answer · 2017-08-08 16:12:03Z

1

var temparray = [[1, 3, 4], [5, 6, 7], [8, 9, 10]];
const final = temparray.map(a => ({ b: a[0], c: a[1], d: a[2] }));

console.log(final);

answered Aug 8, 2017 at 16:12

Erazihel

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Comments

Jonas Wilms · Accepted Answer · 2017-08-08 16:21:45Z

1

Probably, you set obj outside the for loop, therefore the props are overwritten and you push the same object multiple times into the array. Simply move the obj declaration into the loop. And you probably just need the outer loop.

Btw much shorter:

let final = temparray1.map(
 ([b,c,d]) => ({b,c,d})
);

edited Aug 8, 2017 at 16:21

answered Aug 8, 2017 at 16:10

Jonas Wilms

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Comments

Nina Scholz · Accepted Answer · 2017-08-08 17:32:03Z

1

You could use Array#map and return an object with the wanted properties.

var array = [[1, 3, 4], [5, 6, 7], [8, 9, 10]],
    result = array.map(function (a) {
        return { b: a[0], c: a[1], d: a[2] };
    });
    
console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

With ES6, you could map the inner arrays as well with an array for the keys with Object.assign and spread syntax ....

var array = [[1, 3, 4], [5, 6, 7], [8, 9, 10]],
    keys = ['b', 'c', 'd'],
    result = array.map(a => Object.assign(...keys.map((k, i) => ({ [k]: a[i] }))));
    
console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited Aug 8, 2017 at 17:32

answered Aug 8, 2017 at 17:14

Nina Scholz

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Comments

Jonas Wilms · Accepted Answer · 2017-08-11 13:14:49Z

1

Here is what you wanted

var temparray1 = [[1,3,4],[5,6,7],[8,9,10]];
var final = [];
for(var temp in temparray1){
   var obj = {};
   obj['b'] = temparray1[temp][0];
   obj['c'] = temparray1[temp][1];
   obj['d'] = temparray1[temp][2];
   final.push(obj);
}
console.log(final);

Hope this helps!

edited Aug 11, 2017 at 13:14

Jonas Wilms

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answered Aug 8, 2017 at 16:11

zenwraight

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8 Comments

zenwraight Over a year ago

what errors are you getting ? I can send you a live example for it, if you want it

muthukumar selvaraj Over a year ago

the above code push only the last occurene of array [{ b: 8, c: 9, d: 10 } { b: 8, c: 9, d: 10 } { b: 8, c: 9, d: 10 }] @zenwraight array.map function is the correct apporach

zenwraight Over a year ago

I have posted the link of my live example above @muthukumar, please run it and see for yourself

muthukumar selvaraj Over a year ago

Thank you @zenwraight it worked for me i have changed your array to objects really nice and great ` var obj = {};`

muthukumar selvaraj Over a year ago

What issue you are facing @Jonasw, it's is one the perfect answer for the above question

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