Discovering the point of overlap between two arrays of objects featuring variable properties

Question

Discovering the point of overlap between two arrays of objects featuring variable properties

There are two arrays of objects in my code, each with dynamic keys whose names I am unsure of. For example:

array1: [
  {
    level1: 'Shoes',
  }
]

array2: [
  {
    level1: 'Shoes',
    level2: 'Sneakers',
  },
]

I am looking for a way to find the intersection between array1 and array2 without knowing the key names beforehand. The lodash _.intersectionBy method won't work in this case due to the uncertainty of key names in array1.

The expected result should look like [{ level1: 'Shoes' }]. Any suggestions on how to tackle this problem are highly appreciated!

Thank you very much!

javascript arrays lodash

Answer 1

Answer №1

For a comprehensive comparison with every index, you can utilize the following method:

const hierarchy1 = [{
  level1: 'Shoes',
  level3: "xyz"
}]

const hierarchy2 = [{
  level1: 'Shoes',
  level2: 'Sneakers',
}, {
  level3: "xyz"
}]

function intersection(arr1, arr2) {
  let final = []
  // iterate over the first array
  for (let i = 0; i < arr1.length; i++) {
    let element = arr1[i]
    let temp = {}
    
    // loop through all indexes of the second array
    for (let data of arr2) {
      // check each key in data for any intersections
      Object.keys(data).forEach(key => {
        if (data[key] === element[key] && key in element) {
          temp[key] = element[key]
        }
      })
    }
    // push any found intersection into the final array
    if (Object.keys(temp).length) {
      final.push(temp)
    }
  }
  return final
}

console.log(intersection(hierarchy1, hierarchy2))

An enhanced approach involves pre-calculations to optimize the process. You can consolidate all values for a specific key and efficiently verify the presence of a particular value for the given key during iteration.

const hierarchy1 = [{
  level1: 'Shoes',
  level3: "xyz"
},{level2: "abc"}]

const hierarchy2 = [{
  level1: 'Shoes',
  level2: 'Sneakers',
}, {
  level3: "xyz",
  level2: "abc"
}]

function intersection(arr1, arr2) {
  let final = []
  let map = {}
  for(let data of arr2){
    Object.keys(data).forEach(key => {
      map[key] = map[key] || new Set()
      map[key].add(data[key])
    })
  }
  // iterate over the first array
  for (let i = 0; i < arr1.length; i++) {
    let element = arr1[i]
    let temp = {}
    Object.keys(element).forEach(key => {
      if (key in map && map[key].has(element[key])) {
         temp[key] = element[key]
      }
    })
    // push any found intersection into the final array
    if (Object.keys(temp).length) {
      final.push(temp)
    }
  }
  return final
}

console.log(intersection(hierarchy1, hierarchy2))

If your focus is only on comparing corresponding indexes or both arrays, this streamlined method could be implemented:

const hierarchy1 = [{
  level1: 'Shoes',
}]

const hierarchy2 = [{
  level1: 'Shoes',
  level2: 'Sneakers',
},]

function intersection(arr1,arr2){
  let final = []
  for(let i=0; i<arr1.length; i++){
    let element = arr1[i]
    let temp = {}
    Object.keys(element).forEach(key => {
       if(key in arr2[i] && arr2[i][key] === element[key]){
         temp[key] = element[key]
       }
    })
    if(Object.keys(temp).length){
      final.push(temp)
    }
  }
  return final
}

console.log(intersection(hierarchy1,hierarchy2))

Answer 2

For a comprehensive comparison with every index, you can utilize the following method:

const hierarchy1 = [{
  level1: 'Shoes',
  level3: "xyz"
}]

const hierarchy2 = [{
  level1: 'Shoes',
  level2: 'Sneakers',
}, {
  level3: "xyz"
}]

function intersection(arr1, arr2) {
  let final = []
  // iterate over the first array
  for (let i = 0; i < arr1.length; i++) {
    let element = arr1[i]
    let temp = {}
    
    // loop through all indexes of the second array
    for (let data of arr2) {
      // check each key in data for any intersections
      Object.keys(data).forEach(key => {
        if (data[key] === element[key] && key in element) {
          temp[key] = element[key]
        }
      })
    }
    // push any found intersection into the final array
    if (Object.keys(temp).length) {
      final.push(temp)
    }
  }
  return final
}

console.log(intersection(hierarchy1, hierarchy2))

An enhanced approach involves pre-calculations to optimize the process. You can consolidate all values for a specific key and efficiently verify the presence of a particular value for the given key during iteration.

const hierarchy1 = [{
  level1: 'Shoes',
  level3: "xyz"
},{level2: "abc"}]

const hierarchy2 = [{
  level1: 'Shoes',
  level2: 'Sneakers',
}, {
  level3: "xyz",
  level2: "abc"
}]

function intersection(arr1, arr2) {
  let final = []
  let map = {}
  for(let data of arr2){
    Object.keys(data).forEach(key => {
      map[key] = map[key] || new Set()
      map[key].add(data[key])
    })
  }
  // iterate over the first array
  for (let i = 0; i < arr1.length; i++) {
    let element = arr1[i]
    let temp = {}
    Object.keys(element).forEach(key => {
      if (key in map && map[key].has(element[key])) {
         temp[key] = element[key]
      }
    })
    // push any found intersection into the final array
    if (Object.keys(temp).length) {
      final.push(temp)
    }
  }
  return final
}

console.log(intersection(hierarchy1, hierarchy2))

If your focus is only on comparing corresponding indexes or both arrays, this streamlined method could be implemented:

const hierarchy1 = [{
  level1: 'Shoes',
}]

const hierarchy2 = [{
  level1: 'Shoes',
  level2: 'Sneakers',
},]

function intersection(arr1,arr2){
  let final = []
  for(let i=0; i<arr1.length; i++){
    let element = arr1[i]
    let temp = {}
    Object.keys(element).forEach(key => {
       if(key in arr2[i] && arr2[i][key] === element[key]){
         temp[key] = element[key]
       }
    })
    if(Object.keys(temp).length){
      final.push(temp)
    }
  }
  return final
}

console.log(intersection(hierarchy1,hierarchy2))

Answer 3

Answer №2

This method can be utilized to slightly adjust the shape of the data.

let combined = [...array1, ...array2].map(entry=> Object.entries(entry)).flat()
/*
[
  [ 'type', 'Fruit' ],
  [ 'type', 'Vegetable' ],
  [ 'category', 'Apple' ]
]
*/

Subsequently, you can transform it into your desired format

combined.reduce((accumulator,[key,value])=>({
     ...accumulator, 
    [key]: accumulator[key]?accumulator[key]+1:1
  }),{})

/*
{ type: 2, category: 1 }
*/

Answer 4

This method can be utilized to slightly adjust the shape of the data.

let combined = [...array1, ...array2].map(entry=> Object.entries(entry)).flat()
/*
[
  [ 'type', 'Fruit' ],
  [ 'type', 'Vegetable' ],
  [ 'category', 'Apple' ]
]
*/

Subsequently, you can transform it into your desired format

combined.reduce((accumulator,[key,value])=>({
     ...accumulator, 
    [key]: accumulator[key]?accumulator[key]+1:1
  }),{})

/*
{ type: 2, category: 1 }
*/

Discovering the point of overlap between two arrays of objects featuring variable properties

Answer №1

Answer №2

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