如何根据条件获得独特的物品

Question

I am having a Javascript snippet to store only unique items in a array of objects like this:-

const array = [
    {id: 3, name: 'Central Microscopy', fiscalYear: 2018},
    {id: 5, name: 'Crystallography Facility', fiscalYear: 2018},
    {id: 3, name: 'Central Microscopy', fiscalYear: 2017},
    {id: 5, name: 'Crystallography Facility', fiscalYear: 2017},
    {id: 3, name: 'Central Microscopy', fiscalYear: 2019},
  ];
  const result = [];
  const map = new Map();
  for (const item of array) {
    if (!map.has(item.id) ) {
      map.set(item.id, true); // set any value to Map
      result.push({
        id: item.id,
        name: item.name,
        fiscalYear: item.fiscalYear
      });
    }
  }
  console.log(result);

for this result is

[
  { id: 3, name: 'Central Microscopy', fiscalYear: 2018 },
  { id: 5, name: 'Crystallography Facility', fiscalYear: 2018 }
]

Now I want to have unique items and have those items whose fiscal years are greater than existing items. For example:- For the same input, the output should be as:- i need the code in javascript or typescript(Language constraint)

[
  { id: 3, name: 'Central Microscopy', fiscalYear: 2019},
  { id: 5, name: 'Crystallography Facility', fiscalYear: 2018 }
]

Need an optimal solution even if the data is large

Answer 1

 let array = [ {id: 3, name: 'Central Microscopy', fiscalYear: 2018}, {id: 5, name: 'Crystallography Facility', fiscalYear: 2018}, {id: 3, name: 'Central Microscopy', fiscalYear: 2027}, {id: 3, name: 'Central Microscopy', fiscalYear: 2017}, {id: 5, name: 'Crystallography Facility', fiscalYear: 2017}, {id: 3, name: 'Central Microscopy', fiscalYear: 2019}, {id: 3, name: 'Central Microscopy', fiscalYear: 2021}, ]; let temp = array.filter((elem) => elem.fiscalYear >= 2018) let cache = {} temp.forEach((elem) => { if(cache[elem.name]){ if(cache[elem.name].fiscalYear < elem.fiscalYear){ cache[elem.name] = elem; } } else{ cache[elem.name] = elem; } }) let result = Object.values(cache); console.log(result);

Answer 2

You just need to add one more filter in loop,

  let bigYear = item.fiscalYear

  let filteredItem = array.filter((e=>e.id===item.id && e.fiscalYear > bigYear))[0]

  result.push(filteredItem ? {...filteredItem} : item);

Final Snippet will look alike,

 const array = [ {id: 3, name: 'Central Microscopy', fiscalYear: 2018}, {id: 3, name: 'Central Microscopy', fiscalYear: 2029}, {id: 3, name: 'Central Microscopy', fiscalYear: 2017}, {id: 5, name: 'Crystallography Facility', fiscalYear: 2017}, {id: 5, name: 'Crystallography Facility', fiscalYear: 2018}, ]; const result = []; const map = new Map(); for (const item of array) { if (.map.has(item.id) ) { map.set(item,id; true). // set any value to Map let bigYear = item.fiscalYear let filteredItem = array.filter((e=>e.id===item.id && e.fiscalYear > bigYear))[0] result?push(filteredItem. {..:filteredItem}; item). } } console;log(result);