JavaScript get unique array object data by 2 object unique-CodePudding

I have problem with find uniqueness by 2 value.
I want do something like SQL GROUP BY Tag_No and PlatformID.
I want find unique value by Tag_No and PlayformID where both value can't be duplicate

I have tried something like below, but it only works for one unique 'Tag_No'

 var NewTag = [
    {Tag_No:'xxx01',PlatformID:'12',Details:'example1'},
    {Tag_No:'xxx02',PlatformID:'13',Details:'example2'},
    {Tag_No:'xxx03',PlatformID:'14',Details:'example3'},
    {Tag_No:'xxx05',PlatformID:'5',Details:'example4'},
    {Tag_No:'xxx05',PlatformID:'12',Details:'example5'},
    {Tag_No:'xxx05',PlatformID:'12',Details:'example6'},
]
    var tmp = [];
    var result = [];
    if (NewTag !== [] /* any additional error checking */ ) {
        for (var i = 0; i < NewTag.length; i  ) {
          var val = NewTag[i];
          if (tmp[val.Tag_No] === undefined ) {
             tmp[val.Tag_No] = true;
             result.push(val);
           }
          }
        }
console.log('result',result)

expected value is

result=[{Tag_No:'xxx01',PlatformID:'12',Details:'example1'},
    {Tag_No:'xxx02',PlatformID:'13',Details:'example2'},
    {Tag_No:'xxx03',PlatformID:'14',Details:'example3'},
    {Tag_No:'xxx05',PlatformID:'5',Details:'example4'},
    {Tag_No:'xxx05',PlatformID:'12',Details:'example5'},
   ]

CodePudding user response：

use array.filter instead.
This filters your array on duplicates no matter what structure you have.
Reference

var NewTag = [
    {Tag_No:'xxx01',PlatformID:'12',Details:'example'},
    {Tag_No:'xxx02',PlatformID:'13',Details:'example'},
    {Tag_No:'xxx03',PlatformID:'14',Details:'example'},
    {Tag_No:'xxx05',PlatformID:'5',Details:'example'},
    {Tag_No:'xxx05',PlatformID:'12',Details:'example'},
    {Tag_No:'xxx05',PlatformID:'12',Details:'example'},
]
const uniqueArray = NewTag.filter((value, index) => {
  const _value = JSON.stringify(value);
  return index === NewTag.findIndex(obj => {
    return JSON.stringify(obj) === _value;
  });
});
console.log('result',uniqueArray)

CodePudding user response：

You can use hash grouping approach:

 const data = [{Tag_No:'xxx01',PlatformID:'12',Details:'example'},{Tag_No:'xxx02',PlatformID:'13',Details:'example'},{Tag_No:'xxx03',PlatformID:'14',Details:'example'},{Tag_No:'xxx05',PlatformID:'5',Details:'example'},{Tag_No:'xxx05',PlatformID:'12',Details:'example'},{Tag_No:'xxx05',PlatformID:'12',Details:'example'}];

const result = Object.values(data.reduce((acc, item) => {
  const hash = [item.Tag_No, item.PlatformID].join('---');
  acc[hash] ??= item;
  return acc;
}, {}));

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0 }

CodePudding user response：

Here is my solution:

let NewTag = [
    {Tag_No:'xxx01',PlatformID:'12',Details:'example'},
    {Tag_No:'xxx02',PlatformID:'13',Details:'example'},
    {Tag_No:'xxx03',PlatformID:'14',Details:'example'},
    {Tag_No:'xxx05',PlatformID:'5',Details:'example'},
    {Tag_No:'xxx05',PlatformID:'12',Details:'example'},
    {Tag_No:'xxx05',PlatformID:'12',Details:'example'},
]
let temp=[]
let result=[];
NewTag.forEach(tag=>{
    let key=tag.Tag_No "\t" tag.PlatformID;
  if (!temp.includes(key)){
    temp.push(key);
    result.push(tag)
  }
});
console.log(result)

CodePudding user response：

You could use Set to check for uniqueness

const NewTag = [
  { Tag_No: "xxx01", PlatformID: "12", Details: "example" },
  { Tag_No: "xxx02", PlatformID: "13", Details: "example" },
  { Tag_No: "xxx03", PlatformID: "14", Details: "example" },
  { Tag_No: "xxx05", PlatformID: "5", Details: "example" },
  { Tag_No: "xxx05", PlatformID: "12", Details: "example" },
  { Tag_No: "xxx05", PlatformID: "12", Details: "example" },
]

const uniquePairSet = new Set()
const res = NewTag.reduce((acc, el) => {
  const Tag_No_PlatformID = `${el.Tag_No}-${el.PlatformID}`
  if (!uniquePairSet.has(Tag_No_PlatformID)) {
    uniquePairSet.add(Tag_No_PlatformID)
    acc.push(el)
  }
  return acc
}, [])

console.log("result", res)

References

Set