Javascript map operator

Question

I have an object like this

[
  {
    _id: '5ef34e92858bff53bcf69e11',
    factors: [ {factor_id:'factor_id1',calmode:'calmode1',desc:'desc1',webserv:'webserv1',approach:'approach1'},
               {factor_id:'factor_id2',calmode:'calmode2',desc:'desc2',webserv:'webserv2',approach:'approach2'}, 
               {factor_id:'factor_id3',calmode:'calmode3',desc:'desc3',webserv:'webserv3',approach:'approach3'} 
             ],
    clientId: 'Company1',
    module: 'Mod1',
    __v: 0
  },
  {
    _id: '5ef350c9c1acd61e58ef9d08',
    factors: [ {factor_id:'factor_id4',calmode:'calmode4',desc:'desc4',webserv:'webserv4',approach:'approach4'}, 
               {factor_id:'factor_id5',calmode:'calmode5',desc:'desc5',webserv:'webserv5',approach:'approach5'}
             ],
    clientId: 'Company1',
    module: 'Mod2',
    __v: 0
  }
]

I want to create a final list like below

_id, ClientId,module,factor_id,calmode,desc,webserv,approach

I am trying to use map operator within another map operator but its not coming out properly. Any help would be appreciated.

const tmpFacLst = FacExists.map((module) => {
        const Factor = {
          module_id: module._id,
          module: module.module,
        };
        return Factor;
        /*const Fac = module.factors.map((factor)=>{
          const FactorDtl = {
            factor_id:factor._id,
            factor_desc: factor.desc
          }
          return FactorDtl;
        })*/
      });

Update: I am able to achieve using loop

const result = [];
  FacExists.forEach((item) => {
    const Factors = item.factors;
    Factors.forEach((Subitem) => {
      const Facobj = {
        _id: item._id,
        ClientId: item.clientId,
        module: item._id,
        factor_id: Subitem._id,
        calmode: Subitem.calmode,
        desc: Subitem.desc,
        webserv: Subitem.webserv,
      };
      result.push(Facobj);
    });
  });

I want to know is there any better way of doing this without looping.

Your first snippet is broken, it appears you don't have the data for Factor. Could you please paste that in? — richytong
– richytong, Commented Jun 24, 2020 at 17:55
not coming out properly - how's it coming it out exactly? Please add it in the question. — Talha Akbar
– Talha Akbar, Commented Jun 24, 2020 at 17:55
Now I have expanded factors object. I am getting [undefined,undefined] if I return it within the second map operator. If return within the first map operator I am getting the Factor array as it is. I don't want to loop. Please let me know if you need more info. I will also try other options from my end. — Ananth Vivek
– Ananth Vivek, Commented Jun 25, 2020 at 2:33

Anthony · Accepted Answer · 2020-06-24 18:02:05Z

1

An approach like this should work:

const items = [
  {
    _id: "5ef34e92858bff53bcf69e11",
    factors: [
      {
        factor_id: 2,
        calmode: "cal",
        desc: "something",
        webserv: "10.0.0.0",
        approach: "forwards",
      },
    ],
    clientId: "Company1",
    module: "Mod1",
    __v: 0,
  },
  {
    _id: "5ef350c9c1acd61e58ef9d08",
    factors: [
      {
        factor_id: 3,
        calmode: "cal",
        desc: "something",
        webserv: "10.0.0.1",
        approach: "forwards",
      },
    ],
    clientId: "Company1",
    module: "Mod2",
    __v: 0,
  },
];

const result = [];
items.forEach((item) => {
  const { factors, __v, ...rest } = item;
  result.push(...factors.map((factor) => ({ ...factor, ...rest })));
});

console.log(result);

answered Jun 24, 2020 at 18:02

Anthony

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1 Comment

Ananth Vivek Over a year ago

thanks for the answer. I am getting lot of meta data with this answer.

imgnx · Accepted Answer · 2020-06-24 18:08:13Z

0

First, you need to clean your question up a bit because you have the Object keyword / class listed as elements of your factors array, which you call an "object". You should include those objects in your snippets.

let notAnObj = [
  {
    _id: '5ef34e92858bff53bcf69e11',
    factors: [ {_id: 1234, desc: 'bob loblaw'}],
    clientId: 'Company1',
    module: 'Mod1',
    __v: 0
  },
  {
    _id: '5ef350c9c1acd61e58ef9d08',
    factors: [],
    clientId: 'Company1',
    module: 'Mod2',
    __v: 0
  }
]
   console.log(notAnObject)

let arr= [
  {
    _id: '5ef34e92858bff53bcf69e11',
    factors: [ {_id: 1234, desc: 'bob loblaw'}],
    clientId: 'Company1',
    module: 'Mod1',
    __v: 0
  },
  {
    _id: '5ef350c9c1acd61e58ef9d08',
    factors: [],
    clientId: 'Company1',
    module: 'Mod2',
    __v: 0
  }
]

      const tmpFacLst = arr.map((obj) => {
        return {
          _id: obj._id, 
          ClientId: obj.clientId,
          module: obj.module,
          factors: obj.factors.map(factor => {
            return {
              _id: factor._id,
              desc: factor.desc,
            }
          }),
          calmode: undefined,
          webserv: undefined,
          approach: undefined
        };
      });
      console.log(tmpFacLst)

answered Jun 24, 2020 at 18:08

imgnx

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2 Comments

Ananth Vivek Over a year ago

with this I am getting the object which is similar to my original object

imgnx Over a year ago

@AnanthVivek You're missing some sort of reduction (.reduce) or something in your logic. .map is designed to return an array of the same size containing whatever values you place in the object that is returned. I don't understand what the goal is. What does the final schema look like?

rashi jain · Accepted Answer · 2020-06-25 05:02:41Z

0

you can do it like this

 const finalResult = FacExists.reduce((aggregator,fact) => {
      let result =   fact.factors.map(fac=>{
          return {
             _id: fact._id,
             clientId: fact.clientId,
             module: fact.module,
             
             ...fac
          }})
aggregator = [...aggregator,...result];
return aggregator
  },[]);

you will get the desired result in the "finalResult" variable.

edited Jun 25, 2020 at 5:02

answered Jun 24, 2020 at 18:03

rashi jain

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4 Comments

Ananth Vivek Over a year ago

thanks for the answer. I am getting two undefined objects.

rashi jain Over a year ago

can you please share the result which you are getting

Ananth Vivek Over a year ago

Here is the result when I printed the object in console [ undefined, undefined ]. I think its expected as nothing is returned from the outer map iteration.

rashi jain Over a year ago

@AnanthVivek I have edited my answer. This will work.

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