How can I simplify an object iteration code?

Question

Having the next object:

2018: {
    01: {
         01: { key: value }
         02: { key: value }
         03: { key: value }
        },
    02: { ...  }
    },
2019: {
    01: ...

How can I simplify the next code used for getting the values into each day object?

   for (let yearIndex in obj) {
      const year = obj[yearIndex]
      for (let monthIndex in year) {
        const month = year[monthIndex]
        for (let dayIndex in month) {
          const day = month[dayIndex] {
              console.log(day)
          }
        }
      }
    }

The ideal result may be an array with the object of each day:

[{ key: value }, { key: value }, ...]

I think this question is more suited for codereview.stackexchange.com — mhodges
– mhodges, Commented May 15, 2018 at 21:06
Object.entries(obj).map(([yearIndex, year]) => Object.entries(year).map(([monthIndex, month]) => ... could also simply further with Object.values if you don't care about indicies. — Jared Smith
– Jared Smith, Commented May 15, 2018 at 21:06
@mhodges asking how to shorten/simplify code is on topic for SO... — Jared Smith
– Jared Smith, Commented May 15, 2018 at 21:08
@JaredSmith Just said "more suited for". I didn't vote to close or downvote. — mhodges
– mhodges, Commented May 15, 2018 at 21:13

Nina Scholz · Accepted Answer · 2018-05-16 11:19:00Z

1

You could flat the objects by checking the type for a recursive call.

function getFlat(object) {
    return [].concat(
        ...Object
            .values(object)
            .map(value => value && typeof value === 'object' ? getFlat(value) : object)
    );
}

var object = {2018: { '01': { '01': { key: 1 }, '02': { key: 2 }, '03': { key: 3 } }, '02': { '01': { key: 4 }, '02': { key: 5 }, '03': { key: 6 } } }, 2019: { '01': { '01': { key: 7 }, '02': { key: 8 }, '03': { key: 9 } } } };

console.log(getFlat(object));

answered May 16, 2018 at 11:19

Nina Scholz

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Comments

Amr Noman · Accepted Answer · 2018-05-15 21:34:40Z

0

const obj = {
  2018: {
    01: {
      01: '01 first',
      02: '01 second',
    },
    02: {
      01: '02 first'
    }
  },
  2019: {
    01: {}
  }
};

Object.values(obj).forEach(year => {
  Object.values(year).forEach(month => {
    Object.values(month).forEach(day => {
      console.log(day);
    })
  })
})

answered May 15, 2018 at 21:34

Amr Noman

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Comments

Mark · Accepted Answer · 2018-05-15 21:50:15Z

If you are just trying to get the leaves of a tree (in other words, the values that are not themselves objects), you can make a simple recursive function. This works especially well when you don't know exactly how deep the nesting will be.

This will look at each value and if it's an object pass it back through. Otherwise it will push it to an array:

let obj = {2018: {'01': { 01: 'test18_11', 02: 'test18_12', 03: 'test18_13',},'02': { 01: 'test18_21', 02: 'test18_22', 03: 'test18_23',}},2019: {'01': { 01: 'test19_11', 02: 'test19_12', 03: 'test19_13', },'02': { 01: 'test19_21', 02: 'test19_22', 03: 'test19_23',}}}

function recurse(obj, a = []) {
    Object.values(obj).forEach(value => {
        if (typeof value === 'object') return recurse(value, a)
        else  a.push(value)
    })
    return a
}

console.log(recurse(obj))

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