I have an array of JSON objects that I'm trying to convert to CSV where the end format would look something like this in excel:

given data such as...

[
  {
    "url": "https://www.example.com/something",
    "ids": [
      { "id": "F22", "type": "a11y-true" },
      { "id": "C30", "type": "a11y-unknown" }
    ]
  },
  {
    "url": "https://www.example.com/something-else",
    "ids": [
      { "id": "F23", "type": "a11y-true" },
      { "id": "U10", "type": "a11y-unknown" },
      { "id": "CR14", "type": "a11y-unknown" },
      { "id": "RH03", "type": "a11y-true" }
    ]
  }
]

I tried converting the JSON using:

const items = data
const header = Object.keys(items[0])
const csv = [header.join(','),...items.map(row => header.map(fieldName => JSON.stringify(row[fieldName])).join(','))].join('\r\n')
console.log(csv)

but I end up with only the first level converted over:

"https://www.example.com/something",[{"id":"F22","type":"a11y-true"},{"id":"C30","type":"a11y-unknown"}]
"https://www.example.com/something-else",[{"id":"F23","type":"a11y-true"},{"id":"U10","type":"a11y-unknown"},{"id":"CR14","type":"a11y-unknown"},{"id":"RH03","type":"a11y-true"}]

How can I also get the nested arrays converted to CSV so that each {} is a single entry?

CodePudding user response：

There are libraries for working with csv in js but you could just define header fields and then pick those field values when you loop over ids

const data = [{"url":"https://www.example.com/something","ids":[{"id":"F22","type":"a11y-true"},{"id":"C30","type":"a11y-unknown"}]},{"url":"https://www.example.com/something-else","ids":[{"id":"F23","type":"a11y-true"},{"id":"U10","type":"a11y-unknown"},{"id":"CR14","type":"a11y-unknown"},{"id":"RH03","type":"a11y-true"}]}]

const separator = ', '
const header = ["url", "id", 'type']
const body = data.reduce((r, { url, ids }) => {
  ids.forEach((e, i) => {
    const first = i === 0 ? url : ''
    const other = header.slice(1).map(k => e[k]).join(separator)
    r.push([first, other].join(separator))
  })
  return r
}, [])

const result = `${header.join(separator)}\n${body.join('\n')}`

console.log(result)

CodePudding user response：

You can do something like this:

const data = [
  {
    "url": "https://www.example.com/something",
    "ids": [
      { "id": "F22", "type": "a11y-true" },
      { "id": "C30", "type": "a11y-unknown" }
    ]
  },
  {
    "url": "https://www.example.com/something-else",
    "ids": [
      { "id": "F23", "type": "a11y-true" },
      { "id": "U10", "type": "a11y-unknown" },
      { "id": "CR14", "type": "a11y-unknown" },
      { "id": "RH03", "type": "a11y-true" }
    ]
  }
];

const headers = ["url", "id", 'type'];
const res = data.reduce((a,b)=>{
  const [firstRow, ...rest] = b.ids;
  const firstPart = `${b.url},${Object.values(firstRow).join()}\n`
  const restOfThePart = rest.map(it=>`,${Object.values(it).join()}`).join('\n');
  return `${a}${firstPart}${restOfThePart}\n`;
},'');

console.log(`${headers}\n${res}`);