Instructions for transforming rows into columns in JSON format

Question

Instructions for transforming rows into columns in JSON format

Looking to convert an array of JSON objects into a format where rows become columns and the values at the side become column values, similar to the crosstab function in PostgreSQL.

The JSON data looks something like this:

{"marketcode":"01","size":"8,5","amount":1},
{"marketcode":"01","size":"9","amount":1},
{"marketcode":"01","size":"10","amount":0},

I need it to be transformed into this structure:

{"marketcode": "01", "8,5": 1, "9": 1, "10": 0}

I've tried searching for a solution using Lodash, but haven't had any success so far.

javascript arrays json

Answer 1

Answer №1

Here is a potential solution that may meet your requirements:

const transformData = data => {
    const convertedData = data.reduce((result, {id, type, value}) => {
        if (result.has(id)) {
            result.set(id, {...result.get(id), [type]: value});
        } else {
            result.set(id, {id, [type]: value});
        }
        return result;
    }, new Map());
    return [...convertedData.values()];
};

fiddle: https://jsfiddle.net/exampleuser123/abcdefg123/

Answer 2

Here is a potential solution that may meet your requirements:

const transformData = data => {
    const convertedData = data.reduce((result, {id, type, value}) => {
        if (result.has(id)) {
            result.set(id, {...result.get(id), [type]: value});
        } else {
            result.set(id, {id, [type]: value});
        }
        return result;
    }, new Map());
    return [...convertedData.values()];
};

fiddle: https://jsfiddle.net/exampleuser123/abcdefg123/

Answer 3

Answer №2

Hey Bill, I appreciate your help with my question. I initially thought there might be a library for this issue, but ended up coding a solution myself. Thank you so much for your assistance! Here is the code snippet:

companies.forEach((company, index) => {
 // place company in the code
 result[index] = {'company': company};
 // add numbering as columns and quantity in stock as well as sales number if applicable
 a.forEach(item => {
  // check if the numbering corresponds to the company
   if (result[index].company == item.company) {
    if (item.quantity !== undefined && item.sales !== undefined) {
     result[index][item.size] = item.quantity + '/' + item.sales;
    } else {
     result[index][item.size] = item.quantity + '/' + "0";
   }        
  }         
 });
});

fiddle: https://jsfiddle.net/v1hLs5o0/6/

Answer 4

Hey Bill, I appreciate your help with my question. I initially thought there might be a library for this issue, but ended up coding a solution myself. Thank you so much for your assistance! Here is the code snippet:

companies.forEach((company, index) => {
 // place company in the code
 result[index] = {'company': company};
 // add numbering as columns and quantity in stock as well as sales number if applicable
 a.forEach(item => {
  // check if the numbering corresponds to the company
   if (result[index].company == item.company) {
    if (item.quantity !== undefined && item.sales !== undefined) {
     result[index][item.size] = item.quantity + '/' + item.sales;
    } else {
     result[index][item.size] = item.quantity + '/' + "0";
   }        
  }         
 });
});

fiddle: https://jsfiddle.net/v1hLs5o0/6/

Instructions for transforming rows into columns in JSON format

Answer №1

Answer №2

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