Question 211642 in Javascript Question posted in
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Javascript – Is there an efficient way to get an array of objects from another array of objects

I am building an app and I have an array of objects. The objects have a key where the value is an array of objects with key value pairs. I would like to convert this array into an array of just objects

My first array looks like this:

const firstArray = [
  {
    amount: 343,
    code: "RCU8YI0NKS",
    items: [
      {
        productOne: "crust",
        quantity: 2.2,
      },
      {
        productTwo: "dust",
        quantity: 34,
      },
    ],
    user_id: "wewewefwOHG22323kj",
  },
  {
    amount: 343,
    code: "RCU8YI0NKS",
    items: [
      {
        productTwo: "dust",
        quantity: 32,
      },
      {
        productThree: "must",
        quantity: 34,
      },
    ],
    user_id: "m2LgLRD9MEVNAX56JTpRYDkOOjd2",
  },
];

I would like it to look like this array:

const secondArray = [
  {
    amount: 343,
    code: "RCU8YI0NKS",
    crust: 2.2,
    dust: 34,
    user_id: "wewewefwOHG22323kj",
  },
  {
    amount: 343,
    code: "RCU8YI0NKS",
    dust: 32,
    must: 34,
    user_id: "m2LgLRD9MEVNAX56JTpRYDkOOjd2",
  },
];

If anyone knows how to do this, please help.

Thanks.

Tags:

2

Answers


  1. 0

    I can’t see other way to do it without scanning all arrays, except if there’s a kind of pattern I didn’t see in the data.

    The reduce function should do the job :

    function reduce(arr) {
  return arr.map(e => {
    // If you need to not modify original data
    const o = Object.assign({}, e);
    // Otherwise use e directly
    
    for(let item of e.items) {
       let q, name;
       
       for(let p in item) {
          if(p === "quantity") {
            q = item[p];
          } else {
            name = item[p];
          }
       }
       
       o[name] = q;
    }
    
    delete o.items;
    
    return o;
  });
}

const firstArray = [
  {
    amount: 343,
    code: "RCU8YI0NKS",
    items: [
      {
        productOne: "crust",
        quantity: 2.2,
      },
      {
        productTwo: "dust",
        quantity: 34,
      },
    ],
    user_id: "wewewefwOHG22323kj",
  },
  {
    amount: 343,
    code: "RCU8YI0NKS",
    items: [
      {
        productTwo: "dust",
        quantity: 32,
      },
      {
        productThree: "must",
        quantity: 34,
      },
    ],
    user_id: "m2LgLRD9MEVNAX56JTpRYDkOOjd2",
  },
];

console.log(reduce(firstArray));
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  2. 0

    Looks like you just have to turn the items into key value pairs and add them to the object:

    const flatten = arr => arr.map(({items, ...obj}) => items.reduce((agg, {quantity, ...rest}) => (agg[Object.values(rest)[0]] = quantity, agg), obj))

const firstArray = [
  {
    amount: 343,
    code: "RCU8YI0NKS",
    items: [
      {productOne: "crust", quantity: 2.2,},
      {productTwo: "dust", quantity: 34,},
    ],
    user_id: "wewewefwOHG22323kj",
  },
  {
    amount: 343,
    code: "RCU8YI0NKS",
    items: [
      {productTwo: "dust", quantity: 32,},
      {productThree: "must", quantity: 34,},
    ],
    user_id: "m2LgLRD9MEVNAX56JTpRYDkOOjd2",
  },
];

console.log(flatten(firstArray))
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