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Read by key and parse as JSON in JavaScript
Suppose, we have a JSON array like this −
const arr = [{
"data": [
{ "W": 1, "A1": "123" },
{ "W": 1, "A1": "456" },
{ "W": 2, "A1": "4578" },
{ "W": 2, "A1": "2423" },
{ "W": 2, "A1": "2432" },
{ "W": 2, "A1": "24324" }
]
}];We are required to write a JavaScript function that takes in one such array and converts it to the following JSON array −
[
{
"1": [
{
"A1": "123"
},
{
"A1": "456"
}
]
},
{
"2": [
{
"A1": "4578"
},
{
"A1": "2423"
},
{
"A1": "2432"
},
{
"A1": "24324"
}
]
}
];Example
const arr = [{
"data": [
{ "W": 1, "A1": "123" },
{ "W": 1, "A1": "456" },
{ "W": 2, "A1": "4578" },
{ "W": 2, "A1": "2423" },
{ "W": 2, "A1": "2432" },
{ "W": 2, "A1": "24324" }
]
}];
const groupJSON = (arr = []) => {
const preCombined = arr[0].data.reduce((acc, val) => {
acc[val.W] = acc[val.W] || [];
acc[val.W].push({ A1: val.A1 });
return acc;
}, {});
const combined = Object.keys(preCombined).reduce((acc, val) => {
const temp = {};
temp[val] = preCombined[val];
acc.push(temp);
return acc;
}, []);
return combined;
};
console.log(JSON.stringify(groupJSON(arr), undefined, 4));Output
And the output in the console will be −
[
{
"1": [
{
"A1": "123"
},
{
"A1": "456"
}
]
},
{
"2": [
{
"A1": "4578"
},
{
"A1": "2423"
},
{
"A1": "2432"
},
{
"A1": "24324"
}
]
}
]
Updated on: 20-Nov-2020
140 Views
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