Pair two arrays based on a specific key value

Question

Pair two arrays based on a specific key value

I'm currently facing a challenge where I need to associate two arrays of objects, and I could really use some help with this. Explanation :

One array contains various reference products

const array1 = [
{name: peanuts, referenceKey: 0}, 
{name: almond, referenceKey: 1}, 
{name: nuts, referenceKey: 2}, 
{name: cream, referenceKey: 3}
]

The second array consists of open reference products with expiration dates and matching reference keys from array1, along with specific keys for each open product

const array2 = [
 {name: peanuts, expirationDate: "30d", referenceKey:0, otherKey: 42}, 
 {name: peanuts, expirationDate: "20d", referenceKey:0, otherKey: 43}, 
 {name: peanuts, expirationDate: "15h", referenceKey:0, otherKey: 44}, 
 {name: almond, expirationDate: "30d", referenceKey:1, otherKey: 45},
 {name: cream, expirationDate: "1d", referenceKey: 3, otherKey: 46},
 {name:cream, expirationDate: "12h", referenceKey: 3, otherKey: 47}
]

My goal is to calculate the number of the same products in array2 that are open, and store this count in a new array based on array1, like so:

const array3 = [
 {name: peanuts, referenceKey: 0, opened: 3}, 
 {name: almond, referenceKey: 1, opened: 1}, 
 {name: nuts, referenceKey: 2, opened: 0}, 
 {name: cream, referenceKey: 3, opened: 2}
]

I attempted to group array2 by name using the Reduce() method as shown below :

    const groupByName = (products, name) => {
        return products.reduce((acc, obj) => {
            var key = obj[name];
            if (!acc[key]) {
                acc[key] = []
            }
            acc[key].push(obj);
            return acc
        }, [])
    };

    const groupByName = groupByReference(array2, "name")
    console.log(groupByName)

output of groupByName:

  [
    [peanuts:
    [
        {name: peanuts, expirationDate: "30d", referenceKey: 0, otherKey: 42}, 
        {name: peanuts, expirationDate: "20d", referenceKey:0, otherKey: 43}, 
        {name: peanuts, expirationDate: "15h", referenceKey:0, otherKey: 44}, 
    ],
    cream: [
        {name: cream, expirationDate: "1d", referenceKey: 3, otherKey: 46 },
        {name: cream, expirationDate: "12h", referenceKey: 3, otherKey: 47}
    ],
    almond: [
        {name: almond, expirationDate: "30d", referenceKey:1, otherKey: 45},
    ]
 ]

Next, I tried to determine the length of each array but faced difficulties. Despite attempting to utilize the Map() method, it did not provide me with the expected results.

Even when explicitly mentioning an index like groupByName['peanuts'], the console.log() returned the correct array. However, trying to access groupByName['peanuts'].length did not work as intended.

javascript arrays sorting multidimensional-array associative-array

Answer 1

Answer №1

To achieve the desired output and keep track of duplicate objects with the same name, you can utilize an object in your code logic.

const
    items1 = [{ name: "peanuts", identifier: 0 }, { name: "almond", identifier: 1 }, { name: "nuts", identifier: 2 }, { name: "cream", identifier: 3 }],
    items2 = [{ name: "peanuts", expiry: "30d", identifier: 0, key: 42 }, { name: "peanuts", expiry: "20d", identifier: 0, key: 43 }, { name: "peanuts", expiry: "15h", identifier: 0, key: 44 }, { name: "almond", expiry: "30d", identifier: 1, key: 45 }, { name: "cream", expiry: "1d", identifier: 3, key: 46 }, { name: "cream", expiry: "12h", identifier: 3, key: 47 }],
    tempObject = {},
    resultSet = items1.map(obj => tempObject[obj.name] = { ...obj, count: 0 });

items2.forEach(obj => tempObject[obj.name].count++);

console.log(resultSet);

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Answer 2

To achieve the desired output and keep track of duplicate objects with the same name, you can utilize an object in your code logic.

const
    items1 = [{ name: "peanuts", identifier: 0 }, { name: "almond", identifier: 1 }, { name: "nuts", identifier: 2 }, { name: "cream", identifier: 3 }],
    items2 = [{ name: "peanuts", expiry: "30d", identifier: 0, key: 42 }, { name: "peanuts", expiry: "20d", identifier: 0, key: 43 }, { name: "peanuts", expiry: "15h", identifier: 0, key: 44 }, { name: "almond", expiry: "30d", identifier: 1, key: 45 }, { name: "cream", expiry: "1d", identifier: 3, key: 46 }, { name: "cream", expiry: "12h", identifier: 3, key: 47 }],
    tempObject = {},
    resultSet = items1.map(obj => tempObject[obj.name] = { ...obj, count: 0 });

items2.forEach(obj => tempObject[obj.name].count++);

console.log(resultSet);

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Answer 3

Answer №2

const newArr = [...originalArr];
for (let item of newArr) {
  item['status'] = referenceArr.filter(el => el.key === item.key).length;
}

Answer 4

const newArr = [...originalArr];
for (let item of newArr) {
  item['status'] = referenceArr.filter(el => el.key === item.key).length;
}

Answer 5

Answer №3

Based on your initial request, I believe this is the solution you are looking for if I have interpreted your question correctly.

You have the option to group by either name or referenceKey since they are present in both arrays, but not by expirationDate.

const array1 = [
  { name: "apples", referenceKey: 0 },
  { name: "bananas", referenceKey: 1 },
  { name: "oranges", referenceKey: 2 },
  { name: "pears", referenceKey: 3 },
];

const array2 = [
  { name: "apples", expirationDate: "5d", referenceKey: 0, quantity: 4 },
  { name: "apples", expirationDate: "3d", referenceKey: 0, quantity: 5 },
  { name: "apples", expirationDate: "8h", referenceKey: 0, quantity: 6 },
  { name: "bananas", expirationDate: "7d", referenceKey: 1, quantity: 7 },
  { name: "pears", expirationDate: "1d", referenceKey: 3, quantity: 8 },
  { name: "pears", expirationDate: "20h", referenceKey: 3, quantity: 9 },
];

const groupByKey = (fruits, instances, key) => {
  return fruits.reduce((acc, obj) => {
    // Count instances that match
    const matching = instances.filter((instance) => instance[key] === obj[key])
      .length;

    // Add to accumulator array using spread operator for immutability.
    acc = [
      ...acc,
      {
        name: obj.name,
        referenceKey: obj.referenceKey,
        matching,
      },
    ];

    return acc;
  }, []);
};

const array3 = groupByKey(array1, array2, "name");
console.log(array3);

Answer 6

Based on your initial request, I believe this is the solution you are looking for if I have interpreted your question correctly.

You have the option to group by either name or referenceKey since they are present in both arrays, but not by expirationDate.

const array1 = [
  { name: "apples", referenceKey: 0 },
  { name: "bananas", referenceKey: 1 },
  { name: "oranges", referenceKey: 2 },
  { name: "pears", referenceKey: 3 },
];

const array2 = [
  { name: "apples", expirationDate: "5d", referenceKey: 0, quantity: 4 },
  { name: "apples", expirationDate: "3d", referenceKey: 0, quantity: 5 },
  { name: "apples", expirationDate: "8h", referenceKey: 0, quantity: 6 },
  { name: "bananas", expirationDate: "7d", referenceKey: 1, quantity: 7 },
  { name: "pears", expirationDate: "1d", referenceKey: 3, quantity: 8 },
  { name: "pears", expirationDate: "20h", referenceKey: 3, quantity: 9 },
];

const groupByKey = (fruits, instances, key) => {
  return fruits.reduce((acc, obj) => {
    // Count instances that match
    const matching = instances.filter((instance) => instance[key] === obj[key])
      .length;

    // Add to accumulator array using spread operator for immutability.
    acc = [
      ...acc,
      {
        name: obj.name,
        referenceKey: obj.referenceKey,
        matching,
      },
    ];

    return acc;
  }, []);
};

const array3 = groupByKey(array1, array2, "name");
console.log(array3);

Answer 7

Answer №4

To kick things off, I suggest implementing a helper function that tallies all objects containing a specific value when a provided function is applied to them. Here's an example:

countItemsByAttribute(x => x.name)([{name: 'apple', type: 'fruit'}, {name: 'orange', type: 'fruit'}, 
                     {name: 'apple', type: 'fruit'}, {name: 'banana', type: 'fruit'}])
//=> {apple: 2, orange: 1, banana: 1}

This helps us count our objects based on their category (if type is intended to be a string and not reference). Then we can easily loop through our object definitions, incorporating the relevant quantity property from the result (or defaulting to 0 if none found.)

The implementation could resemble this:

const countItemsByAttribute = (fn) => (items) => 
  items.reduce((acc, item, _, __, key = fn(item)) => ({...acc, [key]: (acc[key] || 0) + 1}), {})

const quantity = (definitions, instances, counts = countItemsByAttribute (x => x.category) (instances)) =>
  definitions.map(def => ({...def, quantity: counts[def.category] || 0}))

const productArray = [{product: 'apple', category: 0}, {product: 'orange', category: 1}, {product: 'banana', category: 2}, {product: 'grapefruit', category: 3}]
const inventoryArray = [{product: 'apple', quantityInStock: 10, category: 0}, {product: 'apple', quantityInStock: 5, category: 0}, {product: 'banana', quantityInStock: 20, category: 1}] 

console.log(quantity(productArray, inventoryArray))

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Your idea was definitely heading in the right direction. You could make use of your groupProducts (after resolving a naming conflict between two versions of groupProducts and one of groupByCategory) with a method similar to this:

const groupedByProduct = groupProducts(inventoryArray, "product")

productArray.map(({product, ...rest}) => ({
  product, 
  ...rest, 
  quantity: (groupedByProduct[product] || []).length
}))

Answer 8

To kick things off, I suggest implementing a helper function that tallies all objects containing a specific value when a provided function is applied to them. Here's an example:

countItemsByAttribute(x => x.name)([{name: 'apple', type: 'fruit'}, {name: 'orange', type: 'fruit'}, 
                     {name: 'apple', type: 'fruit'}, {name: 'banana', type: 'fruit'}])
//=> {apple: 2, orange: 1, banana: 1}

This helps us count our objects based on their category (if type is intended to be a string and not reference). Then we can easily loop through our object definitions, incorporating the relevant quantity property from the result (or defaulting to 0 if none found.)

The implementation could resemble this:

const countItemsByAttribute = (fn) => (items) => 
  items.reduce((acc, item, _, __, key = fn(item)) => ({...acc, [key]: (acc[key] || 0) + 1}), {})

const quantity = (definitions, instances, counts = countItemsByAttribute (x => x.category) (instances)) =>
  definitions.map(def => ({...def, quantity: counts[def.category] || 0}))

const productArray = [{product: 'apple', category: 0}, {product: 'orange', category: 1}, {product: 'banana', category: 2}, {product: 'grapefruit', category: 3}]
const inventoryArray = [{product: 'apple', quantityInStock: 10, category: 0}, {product: 'apple', quantityInStock: 5, category: 0}, {product: 'banana', quantityInStock: 20, category: 1}] 

console.log(quantity(productArray, inventoryArray))

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Your idea was definitely heading in the right direction. You could make use of your groupProducts (after resolving a naming conflict between two versions of groupProducts and one of groupByCategory) with a method similar to this:

const groupedByProduct = groupProducts(inventoryArray, "product")

productArray.map(({product, ...rest}) => ({
  product, 
  ...rest, 
  quantity: (groupedByProduct[product] || []).length
}))

Pair two arrays based on a specific key value

Answer №1

Answer №2

Answer №3

Answer №4

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