Cleanest way to convert JavaScript object to multi-dimensional array

Question

I am having an array of object ( rawData ). Each object of this array represents a x-coordinate and y-coordinates of various series (ie, rawData = [(xi,y1i,y2i,..yni)] ). I want to convert it to convertedData , which is an array of the object where each object represents just one series (ie, convertedData = [[(xi,y1i)], [(xi,y2i)]...[(xi,yni)]] )

rawData = [{
    x: 1,
    y1:"1 y1 string", 
    y2:"1 y2 string",
    y3:"1 y3 string",

    yn:"1 yn string",
},{
    x: 2,
    y1:"2 y1 string", 
    y2:"2 y2 string",
    y3:"2 y3 string",

    yn:"2 yn string",
}];

  convertedData = [
    {
      name:"y1",
      data:[
        [1,"1 y1 string"],
        [2,"2 y1 string"],
      ]
    },{
      name:"y2",
      data:[
        [1,"1 y2 string"],
        [2,"2 y2 string"],
      ]
    },{
      name:"y3",
      data:[
        [1,"1 y3 string"],
        [2,"2 y3 string"],
      ]
    },{
      name:"yn",
      data:[
        [1,"1 yn string"],
        [2,"2 yn string"],
      ]
    }
  ];

What is the Javascript way to cleanly attempt this?

---

Work done by me:

 let convertedData = []; rawData = [{ x: 1, y1:"1 y1 string", y2:"1 y2 string", y3:"1 y3 string", yn:"1 yn string", },{ x: 2, y1:"2 y1 string", y2:"2 y2 string", y3:"2 y3 string", yn:"2 yn string", }]; function findDataByName(convertedData, name){ for (let i=0; i<convertedData.length;++i){ if(convertedData[i].name === name) return convertedData[i].data; } return temp; } function convert() { /*initialize the convertedData*/ Object.keys(rawData[0]).forEach((value)=>{ if(value==='x') return; convertedData.push({ name:value,//y1 data:[]//[(xi,y1i)] }) }); /*now loop over rawData and fill convertedData's data array*/ rawData.forEach((obj)=>{ Object.keys(obj).forEach((key)=>{ if(key==='x') return; let data = findDataByName(convertedData,key); data.push([obj['x'], obj[key]]);//pushing a new coordinate }); }) } convert(); console.log(convertedData); 

Answer 1

It all depends on what you would regard cleanest. There are several programming strategies, each with their pros and cons.

Here is a functional programming approach, using Array prototype functions and an ES6 Map as temporary hash to group the data by x value.

 const rawData = [{x: 1,y1:"1 y1 string",y2:"1 y2 string",y3:"1 y3 string",yn:"1 yn string",},{x: 2,y1:"2 y1 string",y2:"2 y2 string",y3:"2 y3 string", yn:"2 yn string", }]; const convertedData = Array.from(rawData.reduce( (map, obj) => Object.keys(obj).filter(key => key != "x").reduce( (map, key) => map.set(key, (map.get(key) || []).concat([[obj.x, obj[key]]])), map ), new Map ), ([name, data]) => ({name, data})); console.log(convertedData); 

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Answer 2

This is a pretty good use case of reduce on the outer array followed by looping over the entries of each object.

 let rawData = [{x: 1,y1:"1 y1 string", y2:"1 y2 string",y3:"1 y3 string",yn:"1 yn string",},{x: 2,y1:"2 y1 string", y2:"2 y2 string",y3:"2 y3 string",yn:"2 yn string",}]; let obj = rawData.reduce((o, item) => { Object.entries(item).forEach(([key, val]) => { if (key === 'x') return if (o.hasOwnProperty(key)){ let data = o[key].data data.push([data.length+1, val]) } else { o[key] = {name: key, data: [[1, val]]} } }) return o }, {}) // obj is an object, but you are only interested in the values: console.log(Object.values(obj)) 

Answer 3

It's not beautiful but it does do the trick. The only really janky part is the Number(item[1][0]) which would strip 1 from ["y2", "1 y2 string"]

//Flatten the data
const y = rawData.map(item => {
  return Object.entries(item).filter(entry => entry[0] !== 'x');
}).reduce((acc, curr) => acc.concat(curr), []);

//Create yheader array: ["y1", "y2"..., "yn"];
const yHeaders = [... new Set(y.map(item => item[0]))];

//for each y header, build the corresponding data object 
const clean = yHeaders.map(targetHeader => {
  return {
    name: targetHeader,
    data: y.filter(item => item[0] === targetHeader).map(item => [ Number(item[1][0]), item])
  }
});