Check for non null array during filtering an object

Question

Trying to filter the object to return only non null values.

Below is excerpt from my code. How do I check for non null values in the array job in this case?

const name = null,
  age = '25',
  job = [null];

const obj = {
  name,
  age,
  job
};

const result = Object.fromEntries(
  Object.entries(obj).filter(([_, value]) => value)
);

console.log(result)

Could anyone please help?

I was expecting the result to be

{
  "age": "25"
}

Arrays are truthy. Pop open your developer console and type !![]. And even if empty arrays were falsy, yours is not empty — Taplar
– Taplar, Commented Dec 18, 2020 at 23:26
You will have to check typeof for each value and if it is an array then traverse through the array and check. — Rinkesh Golwala
– Rinkesh Golwala, Commented Dec 18, 2020 at 23:27
Also, what about scenarios where an array has mixed values, i.e. ['developer', null]? Would you want to reject that array or keep it? — Terry
– Terry, Commented Dec 18, 2020 at 23:28
Less smelly, if it is expected only ever be one single value, the usage of an array is unnecessary — Taplar
– Taplar, Commented Dec 18, 2020 at 23:39

CertainPerformance · Accepted Answer · 2020-12-18 23:34:58Z

2

First map the array in the entries to keep only truthy values, then filter the entries by whether the entry is truthy and not a 0-length array:

const name = null,
  age = '25',
  job = [null];

const obj = {
  name,
  age,
  job
};

const result = Object.fromEntries(
  Object.entries(obj)
    .map(
      ([key, value]) => [key, Array.isArray(value) ? value.filter(v => v) : value]
    )
    .filter(([, value]) => value && (!Array.isArray(value) || value.length))
);

console.log(result)

answered Dec 18, 2020 at 23:34

CertainPerformance

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Comments

Unmitigated · Accepted Answer · 2020-12-18 23:32:40Z

0

If your arrays can only have one element, you can check if the value[0] is truthy as well.

const name = null,
  age = '25',
  job = [null];

const obj = {
  name,
  age,
  job
};

const result = Object.fromEntries(
  Object.entries(obj).filter(([_, value]) => value && value[0])
);

console.log(result)

answered Dec 18, 2020 at 23:32

Unmitigated

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Comments

pilchard · Accepted Answer · 2020-12-19 00:05:23Z

0

This can be done as follows:

const name = null,
  age = '25',
  job = [null, 29];

const obj = {
  name,
  age,
  job
};
let result = {
}
for (prop in obj) {
  if (obj[prop]) {
    if (Array.isArray(obj[prop])) {
      result[prop] = obj[prop].filter(function (element) {
        return element != null;
      })
    }
    else {
      result[prop] = obj[prop];
    }
  }
}

console.log(result)

edited Dec 19, 2020 at 0:05

pilchard

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answered Dec 18, 2020 at 23:54

MAHESH PALIWAL

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