How to find array of object if current value more closest to now date?-CodePudding

I have JSON file that contain year value in string in edu_end_year. I want to choose one if the data more than one in same emp_id when the edu_end_year is closest to date now.

here's the data:

educations = [
    {
        "emp_id": 1,
        "edu_degree": "SMA",
        "edu_end_year": 2011
    },
    {
        "emp_id": 1,
        "edu_degree": "S1",
        "edu_end_year": 2016
    },
    {
        "emp_id": 2,
        "edu_degree": "S1",
        "edu_end_year": 2016
    }
]

here's result what i expected :

[
    {
        "emp_id": 1,
        "edu_degree": "S1",
        "edu_end_year": 2016
    },
    {
        "emp_id": 2,
        "edu_degree": "S1",
        "edu_end_year": 2016
    }
]

I was trying using filter() and find(), but still no luck.

please let me know if you need more information to solve that problem if it's still not enough.

CodePudding user response：

One way to solve this would be to use a Map and store the education with the highest edu_end_year for each emp_id.

const maxEducations = new Map();
for (const education of educations) {
  const maxEducation = maxEducations.get(education.emp_id);
  if (maxEducation && education.edu_end_year <= maxEducation.edu_end_year) continue;
  maxEducations.set(education.emp_id, education);
}

The if-statment will skip the rest of the iteration if maxEducation is found and the current education.edu_end_year less or equal to maxEducation.edu_end_year.

If either maxEducation is not set, or we encounter a new max edu_end_year then the current education is set as the new maximum.

Once you've iterated through all educations and you'd like to have an array of the values, you can do the following

const result = Array.from(maxEducations.values());

const educations = [
    {
        "emp_id": 1,
        "edu_degree": "SMA",
        "edu_end_year": 2011
    },
    {
        "emp_id": 1,
        "edu_degree": "S1",
        "edu_end_year": 2016
    },
    {
        "emp_id": 2,
        "edu_degree": "S1",
        "edu_end_year": 2016
    }
];

const maxEducations = new Map();
for (const education of educations) {
  const maxEducation = maxEducations.get(education.emp_id);
  if (maxEducation && education.edu_end_year <= maxEducation.edu_end_year) continue;
  maxEducations.set(education.emp_id, education);
}

console.log(Array.from(maxEducations.values()));

CodePudding user response：

I don't know this code efficient to handle big data or not, but that's work to fix if emp_id is same.

suggestion use this code after pagination

educations = [
    {
        "emp_id": 1,
        "edu_degree": "SMA",
        "edu_end_year": 2011
    },
    {
        "emp_id": 1,
        "edu_degree": "S1",
        "edu_end_year": 2016
    },
    {
        "emp_id": 2,
        "edu_degree": "S1",
        "edu_end_year": 2016
    },
    {
        "emp_id": 2,
        "edu_degree": "S1",
        "edu_end_year": 2016
    },
    {
        "emp_id": 2,
        "edu_degree": "S1",
        "edu_end_year": 2016
    }
]

for (let i = educations.length -1; i > 0; i--){
    if(educations[i].emp_id === educations[i-1].emp_id){
        educations.splice(i, i)
  }
}
console.log(educations)

CodePudding user response：

You can use Array.reduce

use reduce() to loop through each element
Check your final array (acc) has items by checking emp_id into list
If it's first item then insert into
If same emp_id exists then check which year is greater
Replace newer year record into final array

educations = [
    {
        "emp_id": 1,
        "edu_degree": "SMA",
        "edu_end_year": 2011
    },
    {
        "emp_id": 1,
        "edu_degree": "S1",
        "edu_end_year": 2016
    },
    {
        "emp_id": 2,
        "edu_degree": "S1",
        "edu_end_year": 2015
    },
    {
        "emp_id": 2,
        "edu_degree": "S13",
        "edu_end_year": 2017
    },
    {
        "emp_id": 2,
        "edu_degree": "S14",
        "edu_end_year": 2016
    }
]

finalArr = educations.reduce((acc, prev) => {
  if(!acc.find(x=>x.emp_id === prev.emp_id)){
    acc.push(prev)
  }
  else{
    let record = acc.find(x=>x.emp_id === prev.emp_id);
    if(prev.edu_end_year >= record.edu_end_year){
      let index = acc.findIndex(x=>x.emp_id === prev.emp_id);
      acc[index] = prev;
    }
  }
  
  return acc;
}, []);
console.log(finalArr)

CodePudding user response：

This should do it:

const educations = [{"emp_id": 1,"edu_degree": "SMA","edu_end_year": 2011},
    {"emp_id": 1,"edu_degree": "S1","edu_end_year": 2016},
    {"emp_id": 3,"edu_degree": "S3","edu_end_year": 2014},
    {"emp_id": 2,"edu_degree": "S1","edu_end_year": 2016}];
const cyear=new Date().getFullYear(),
  year=educations.reduce((a,c)=>c.edu_end_year > a.edu_end_year ? c: a).edu_end_year,
  res=educations.filter(d=>d.edu_end_year==year)
 
console.log(res);

In the .reduce() loop I first calculate the closest day to today and store it in year. This is assuming that all the dates are in the past. That way I don't even need to know the current date. In the following .filter() loop I then extract only those elements with d.edu_end_year==year.