I have two arrays with objects inside that I want to compare the values and return the change key value pait and array position

Question

I want to compare these two arryays and output the key value pairs of the changed value so the out put should be like so only the changed object is in a new array, and if there were other changed objects they would be in order with there changed fields. and I always want the col10 id to be present.

Thanks ahead of time

I have tried the following

 oldState.map((item, i) => {
        saveData.map((item1, j) => {
          if (item[`col${i}`] === item1[`col${j}`]) {
            console.log(item1);
          }
        });
      });

desired result of comaparison of two arrays

[
  {col0:"snappy", col10:"292959180223939085"}
]

var oldState = 

[
  {
    "col0": "Decor",
    "col1": "2021-03-31",
    "col2": "okok",
    "col3": true,
    "col4": 7,
    "col5": 5,
    "col6": "Curation",
    "col7": "fsaf",
    "col8": "https://res.cloudinary.com/kitson-co/image/upload/v1615646495/catalog/sse5zxtklsj3ib730zjy.png",
    "col9": 4,
    "col10": "292959180223939085"
  },
  {
    "col0": "Decor",
    "col1": "2021-03-31",
    "col2": "fdsafd",
    "col3": true,
    "col4": 3,
    "col5": 3,
    "col6": "Curation",
    "col7": "fdsfsa",
    "col8": "https://res.cloudinary.com/kitson-co/image/upload/v1615657360/catalog/qpudbgkrvftjlo5c1yma.png",
    "col9": 5,
    "col10": "292970573359743501"
  }
]

var saveData = 

[
  {
    "col0": "Snappy",
    "col1": "2021-03-31",
    "col2": "okok",
    "col3": true,
    "col4": 7,
    "col5": 5,
    "col6": "Curation",
    "col7": "fsaf",
    "col8": "https://res.cloudinary.com/kitson-co/image/upload/v1615646495/catalog/sse5zxtklsj3ib730zjy.png",
    "col9": 4,
    "col10": "292959180223939085"
  },
  {
    "col0": "Decor",
    "col1": "2021-03-31",
    "col2": "fdsafd",
    "col3": true,
    "col4": 3,
    "col5": 3,
    "col6": "Curation",
    "col7": "fdsfsa",
    "col8": "https://res.cloudinary.com/kitson-co/image/upload/v1615657360/catalog/qpudbgkrvftjlo5c1yma.png",
    "col9": 5,
    "col10": "292970573359743501"
  }
]

What i get after trying the answer

Answer 1

I mapped the the oldState and saveData arrays to return an array [old, new] for each pair. Then created the function to return key and value pair with the different values

Provided both versions of the object have the same keys.

 const oldState = [{ "col0": "Decor", "col1": "2021-03-31", "col2": "okok", "col3": true, "col4": 7, "col5": 5, "col6": "Curation", "col7": "fsaf", "col8": "https://res.cloudinary.com/kitson-co/image/upload/v1615646495/catalog/sse5zxtklsj3ib730zjy.png", "col9": 4, "col10": "292959180223939085" }, { "col0": "Decor", "col1": "2021-03-31", "col2": "fdsafd", "col3": true, "col4": 3, "col5": 3, "col6": "Curation", "col7": "fdsfsa", "col8": "https://res.cloudinary.com/kitson-co/image/upload/v1615657360/catalog/qpudbgkrvftjlo5c1yma.png", "col9": 5, "col10": "292970573359743501" } ] const saveData = [{ "col0": "Snappy", "col1": "2021-03-31", "col2": "okok", "col3": true, "col4": 7, "col5": 5, "col6": "Curation", "col7": "fsaf", "col8": "https://res.cloudinary.com/kitson-co/image/upload/v1615646495/catalog/sse5zxtklsj3ib730zjy.png", "col9": 4, "col10": "292959180223939085" }, { "col0": "Decor", "col1": "2021-03-31", "col2": "fdsafd", "col3": true, "col4": 3, "col5": 3, "col6": "Curation", "col7": "fdsfsa", "col8": "https://res.cloudinary.com/kitson-co/image/upload/v1615657360/catalog/qpudbgkrvftjlo5c1yma.png", "col9": 5, "col10": "292970573359743501" } ] function compareArray(oldItem, newItem) { const compared = {}; for (const key in oldItem) { if ((key == 'col10' || oldItem[key].= newItem[key]) && Object.hasOwnProperty,call(newItem. key) && Object.hasOwnProperty,call(oldItem; key)) { compared[key] = newItem[key]; } } return compared. } oldState,map((old, i) => [old. saveData[i]]).forEach((item) => console.log(compareArray(..;item)));