Map object changing array of objects

Question

On an Angular application I have the following object with an array of requirements:

var source = {
  position: "xyz",
  requirements: [
    { a: { code: "a1", name: "a1" }, b: { code: "b1", name: "b1" } },
    { a: { code: "a2", name: "a2" }, b: { code: "b2", name: "b2" } }
  ]
};

I need to create a copy of this object as follows:

var target = {
  position: "xyz",
  requirements: [
    { acode: "a1", bcode: "b1" },
    { acode: "a2", bcode: "b2" }
  ]
};

So only the 'a' codes and 'b' codes are picked ...

What would be the best way to map such an object?

.map(x => {acode: x.a.code, bcode: x.b.code})

georg
– georg

2016-08-29 15:23:42 +00:00
Commented Aug 29, 2016 at 15:23 — georg
– georg, Commented Aug 29, 2016 at 15:23

KevBot · Accepted Answer · 2016-08-29 16:00:15Z

3

You can use Object.assign() to "copy" the object in this case. Then just map over the requirements.

var source = {
  position: "xyz",
  requirements: [
    { a: { code: "a1", name: "a1" }, b: { code: "b1", name: "b1" } },
    { a: { code: "a2", name: "a2" }, b: { code: "b2", name: "b2" } }
  ]
};

var copy = Object.assign({}, source);
copy.requirements = copy.requirements.map(item => {
  return {acode: item.a.code, bcode: item.b.code}
});

console.log(source);
console.log(copy);

edited Aug 29, 2016 at 16:00

answered Aug 29, 2016 at 15:28

KevBot

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6 Comments

Miguel Moura Over a year ago

I need to create a copy of source, e.g., target with the new format. Not changing the source. This is I am sending target to an API in the required format but not wanting to change the format that the client is using.

KevBot Over a year ago

@MiguelMoura, sorry I missed that case. I've updated the answer to "copy" the original object.

Miguel Moura Over a year ago

using simply "var copy = source" would not make the same as Object.create?

KevBot Over a year ago

Nope, doing var copy = source will not work because copy would then point to the same piece of memory as source. Which means that any changes to copy would be reflected in source.

georg Over a year ago

Object.create() doesn't make copies, you probably want Object.assign({}, source).

|

Rafi Ud Daula Refat · Accepted Answer · 2016-08-29 15:33:58Z

You can simply loop around and do this

var source = {
  position: "xyz",
  requirements: [
    { a: { code: "a1", name: "a1" }, b: { code: "b1", name: "b1" } },
    { a: { code: "a2", name: "a2" }, b: { code: "b2", name: "b2" } }
  ]
};

var target ={};
var innerArray = [];
for(var key in source) {
  if (source.hasOwnProperty(key)) {
    if(typeof source[key] === 'string') {
       target[key] = source[key];   
    } else {
      for(var i = 0; i < source[key].length; i++) {
        var temp = {};
        temp.acode = source[key][i].a.code;
        temp.bcode = source[key][i].b.code;
        innerArray.push(temp);
      }
      target[key] = innerArray;    
    }
  }
}

console.log(target);

Here is the fiddle https://jsfiddle.net/Refatrafi/Lgryf2kv/12/

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