How to count occurrence of a given number in an Array using ReactJS

Question

I store the result of my Flask server in this.state.jsondata and it's a JSON like this {label{},text{}}

export default class Success extends React.Component {

    constructor(props) {
        super();
        if (props.location.state) {
            this.state = {
                jsondata: props.location.state.referrer,
                upload: true
                
            } //put jsons data in state object
            toast.success('Upload success')
        } else {
            this.state = {
                upload: false
            }
        }
    }    
...

So in order to find occurrence in label I converted my JSON to an Array and coded something to find the occurrences but my problem is that I want to find the occurrence of 0, 1 and 2 not only 0. You can already see that I'll need to duplicate my code three times and it's a no-go.

render() {
        const arr = []
        Object.keys(this.state.jsondata.label).forEach(key => arr.push({id: key, value: this.state.jsondata.label[key]}))
        
        var search = 0;
        var count = arr.reduce(function(n, val) {
            return n + (val.value === search);
        }, 0);
...

How can I modify my code to be able to get occurrence of a given number ?

Here is the whole code: https://jsfiddle.net/p9qxktgz/3/

[EDIT]

this.state.jsondata looks like this :

{
   "label":{
      "0":0,
      "1":0,
      "2":0,
      "3":0,
      "4":0
   },
   "text":{
      "0":"- Awww, c'est un bummer. Tu devrais avoir david carr du troisième jour pour le faire. ;ré",
      "1":"Est contrarié qu'il ne puisse pas mettre à jour son facebook en le télémaignant ... et peut-être pleurer en conséquence, l'école aujourd'hui aussi. blabla!",
      "2":"J'ai plongé plusieurs fois pour la balle. A réussi à économiser 50% le reste sort de limites",
      "3":"Tout mon corps a des démangeaisons et comme si c'était en feu",
      "4":"Non, il ne se comporte pas du tout. je suis en colère. pourquoi suis-je ici? Parce que je ne peux pas vous voir partout."
   }
}

the arr is like this :

There isn't a "expected" output, all I want to do is to be able to get as an output the occurrence of each diffrent values in arr

What is the expected output for the screenshot which you have posted ? — Shyam, Jun 02 '21 at 18:10
as an output I want the number of occurrence for a given number (here the occurrence of 0 is 5) — Jérôme Vial, Jun 02 '21 at 18:12
It would be nice so the object could be like { 0:5, 1:0, 2:1} for example — Jérôme Vial, Jun 02 '21 at 18:15

Shyam · Accepted Answer · 2021-06-02T18:28:59.380

0

const jsonInput = {
   "label":{
      "0":0,
      "1":0,
      "2":0,
      "3":0,
      "4":0
   }
   }

const occurrenceMap = Object.values(jsonInput.label).reduce((finalMap, item) => {
  finalMap[item] = ++finalMap[item] || 1; 
  
  return finalMap;
} , {})

console.log(occurrenceMap)

edited Jun 02 '21 at 18:28

answered Jun 02 '21 at 18:20

Shyam

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edited the answer to get the occurrence from the json directly instead of converting it into an array and then using that to find the occurrence it . – Shyam Jun 02 '21 at 18:31

How to count occurrence of a given number in an Array using ReactJS

1 Answers1