Sorting through boolean values within an array of objects

Question

Sorting through boolean values within an array of objects

Here is an example of an array:

 const appoint =[
  { a: "asas",
    b:{au: false, h:false,l:true}
  },
  { a: "avd",
    b:{au: true, h:false,l:true}
  },
  { a: "as", b:{au: true, h:false,l:false}
  }];

My goal is to filter out falsy values when accessing property b. I attempted to achieve this using multiple map() functions like this:

const result = appoint.map(elem => elem.b.)
const finalresult = result.map(
         item =>item.filter(
              (item, value)=> item[value] === false )
          )

javascript arrays filter

Answer 1

Answer №1

To start, you can utilize the map function to create a new array that only contains values from the b key. Next, use the reduce method and within the callback function of reduce, employ for..in loop to iterate through the object and extract keys that are true.

const appoint = [{
    a: "asas",
    b: {
      au: false,
      h: false,
      l: true
    }
  },
  {
    a: "avd",
    b: {
      au: true,
      h: false,
      l: true
    }
  },
  {
    a: "as",
    b: {
      au: true,
      h: false,
      l: false
    }
  }
];

let filtered = appoint.map(function(item) {
  return item.b;
}).reduce(function(acc, curr) {
  for (let keys in curr) {
    if (curr[keys]) {
      acc.push(keys);
    }
  }

  return acc;
}, []);
console.log(filtered)

Answer 2

To start, you can utilize the map function to create a new array that only contains values from the b key. Next, use the reduce method and within the callback function of reduce, employ for..in loop to iterate through the object and extract keys that are true.

const appoint = [{
    a: "asas",
    b: {
      au: false,
      h: false,
      l: true
    }
  },
  {
    a: "avd",
    b: {
      au: true,
      h: false,
      l: true
    }
  },
  {
    a: "as",
    b: {
      au: true,
      h: false,
      l: false
    }
  }
];

let filtered = appoint.map(function(item) {
  return item.b;
}).reduce(function(acc, curr) {
  for (let keys in curr) {
    if (curr[keys]) {
      acc.push(keys);
    }
  }

  return acc;
}, []);
console.log(filtered)

Answer 3

Answer №2

The 'elem.b' property is an object, not an array, which means that you cannot use the filter method on it directly. One way to work around this limitation is by doing the following:

const bArray = appoint.map(elem => elem.b)
const finalResult = bArray.map(b => {
  const bKeys = Object.keys(b)
  const filtered = {}
  bKeys.forEach(key => {
    if (!b[key]) filtered[key] = false
  })
  return filtered
})

Answer 4

The 'elem.b' property is an object, not an array, which means that you cannot use the filter method on it directly. One way to work around this limitation is by doing the following:

const bArray = appoint.map(elem => elem.b)
const finalResult = bArray.map(b => {
  const bKeys = Object.keys(b)
  const filtered = {}
  bKeys.forEach(key => {
    if (!b[key]) filtered[key] = false
  })
  return filtered
})

Answer 5

Answer №3

A custom function called getKeysBy() can be created to take an object and a predicate as input, then return the keys that meet the criteria set by the predicate.

One way to retrieve all these keys is by utilizing the Array.flatMap() method in conjunction with the getKeysBy() function.

const appoint = [{"a":"asas","b":{"au":false,"h":false,"l":true}},{"a":"avd","b":{"au":true,"h":false,"l":true}},{"a":"as","b":{"au":true,"h":false,"l":false}}]
  
const getKeysBy = (predicate, obj) => 
  Object.entries(obj)
  .filter(([, v]) => predicate(v))
  .map(([k]) => k)
  
const result = appoint.flatMap(o => getKeysBy(v => v !== false, o.b))

console.log(result)

Answer 6

A custom function called getKeysBy() can be created to take an object and a predicate as input, then return the keys that meet the criteria set by the predicate.

One way to retrieve all these keys is by utilizing the Array.flatMap() method in conjunction with the getKeysBy() function.

const appoint = [{"a":"asas","b":{"au":false,"h":false,"l":true}},{"a":"avd","b":{"au":true,"h":false,"l":true}},{"a":"as","b":{"au":true,"h":false,"l":false}}]
  
const getKeysBy = (predicate, obj) => 
  Object.entries(obj)
  .filter(([, v]) => predicate(v))
  .map(([k]) => k)
  
const result = appoint.flatMap(o => getKeysBy(v => v !== false, o.b))

console.log(result)

Answer 7

Answer №4

If you're looking to achieve something similar, consider the following approach:

let data = [{
    item: "apple",
    details: {
        fresh: false,
        organic: true,
        sweet: true
    }
}, {
    item: "banana",
    details: {
        fresh: true,
        organic: false,
        sweet: true
    }
}, {
    item: "orange",
    details: {
        fresh: true,
        organic: false,
        sweet: false
    }
}, {
    item: "grapes",
    details: {
        fresh: false,
        organic: true,
        sweet: true
    }
}]

let result = data.filter((entry) => {
    let keys = Object.keys(entry.details)
    entry.details = keys.filter((key) => {
        if (entry.details[key]) {
            return key
        }
    })
    if (!Object.keys(entry.details).length) {
        entry.details = []
    }
    return entry;
})
console.log(result)

The output will be:

[
    {
        "item": "apple",
        "details": [
            "organic",
            "sweet"
        ]
    },
    {
        "item": "banana",
        "details": [
            "fresh",
            "sweet"
        ]
    },
    {
        "item": "orange",
        "details": [
            "fresh"
        ]
    },
    {
        "item": "grapes",
        "details": [
            "organic",
            "sweet"
        ]
    }
]

In case none of the values are true, an empty array will be returned for that specific entry.

Answer 8

If you're looking to achieve something similar, consider the following approach:

let data = [{
    item: "apple",
    details: {
        fresh: false,
        organic: true,
        sweet: true
    }
}, {
    item: "banana",
    details: {
        fresh: true,
        organic: false,
        sweet: true
    }
}, {
    item: "orange",
    details: {
        fresh: true,
        organic: false,
        sweet: false
    }
}, {
    item: "grapes",
    details: {
        fresh: false,
        organic: true,
        sweet: true
    }
}]

let result = data.filter((entry) => {
    let keys = Object.keys(entry.details)
    entry.details = keys.filter((key) => {
        if (entry.details[key]) {
            return key
        }
    })
    if (!Object.keys(entry.details).length) {
        entry.details = []
    }
    return entry;
})
console.log(result)

The output will be:

[
    {
        "item": "apple",
        "details": [
            "organic",
            "sweet"
        ]
    },
    {
        "item": "banana",
        "details": [
            "fresh",
            "sweet"
        ]
    },
    {
        "item": "orange",
        "details": [
            "fresh"
        ]
    },
    {
        "item": "grapes",
        "details": [
            "organic",
            "sweet"
        ]
    }
]

In case none of the values are true, an empty array will be returned for that specific entry.

Sorting through boolean values within an array of objects

Answer №1

Answer №2

Answer №3

Answer №4

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