JS Simplify Restructuring of Array to Object Conversion with Array.map() and Array.reduce()

Question

I have an API call which returns data in such format:

const testScheduleData = [
    {
        DATE: "2021-06-20",
        SELECTED: false,
        STARTINGDAY: true,
        ENDINGDAY: true,
        STATUS: "WORK",
        COLOR: "green",
    },
    {
        DATE: "2021-06-21",
        SELECTED: false,
        STARTINGDAY: true,
        ENDINGDAY: true,
        STATUS: "HALFDAY",
        COLOR: "green",
    },
];

I need to restructure it to an object of objects in such format:

Object {
  "2021-06-20": Object {
    "color": "green",
    "endingDay": true,
    "selected": false,
    "startingDay": true,
  },
  "2021-06-21": Object {
    "color": "green",
    "endingDay": true,
    "selected": false,
    "startingDay": true,
  },

the way I do it is first to map the testScheduleData to array (ignore item.STATUS for now):

const datesArr = testScheduleData.map((item, index) => ({
    [item.DATE]: {
        startingDay: item.STARTINGDAY,
        endingDay: item.ENDINGDAY,
        color: item.COLOR,
        selected: item.SELECTED,
    },
}));

and then use reduce to create an object from it:

var datesObj = datesArr(function (result, item) {
    var key = Object.keys(item)[0];
    result[key] = item[key];
    return result;
}, {});

which returns the correct result, but seems like an overdo. Is there a way to simplify those two steps?

const datesArr = Object.assign({}, ...datesArr). But probably you should just do the mapping inside the reduce callback — Bergi
– Bergi, Commented Jun 10, 2021 at 8:07
Do the properties have to be camelCase? If not, then (a slightly modified version of georgs answer): Object.fromEntries(testScheduleData.map(item => { let {DATE, ...rest} = item; return [DATE, rest]; })) — Andreas
– Andreas, Commented Jun 10, 2021 at 8:15
Unfortunately, yes. The way api works with database is a must uppercase. The way the library works (which uses the formatted object) is a must camel case :( — denistepp
– denistepp, Commented Jun 10, 2021 at 8:20

sancoLgates · Accepted Answer · 2021-06-10 08:08:49Z

3

try the code below, you just need to map and push into an object

let obj = {}

const testScheduleData = [
    {
        DATE: "2021-06-20",
        SELECTED: false,
        STARTINGDAY: true,
        ENDINGDAY: true,
        STATUS: "WORK",
        COLOR: "green",
    },
    {
        DATE: "2021-06-21",
        SELECTED: false,
        STARTINGDAY: true,
        ENDINGDAY: true,
        STATUS: "HALFDAY",
        COLOR: "green",
    },
];

testScheduleData.map(row => {
   obj[row.DATE] = row
})

console.log(obj)

answered Jun 10, 2021 at 8:08

sancoLgates

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sancoLgates Over a year ago

our job is to enlighten, OP can edit as he please

georg · Accepted Answer · 2021-06-10 08:11:08Z

2

You can have the map callback return pairs [key, value] and then apply Object.fromEntries or new Map to the result:

datesObj = Object.fromEntries(
    testScheduleData.map(it => [
        it.DATE, {
            startingDay: it.STARTINGDAY,
            endingDay: it.ENDINGDAY,
            color: it.COLOR,
            selected: it.SELECTED,
        }
    ]))

answered Jun 10, 2021 at 8:11

georg

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1 Comment

denistepp Over a year ago

Neat solution! Thank you!

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