Convert plain text data into an object with arrays based on formatting-CodePudding

What is the best way to convert plain text data like:

[group a]
a
b
c
[group b]
a
d
f

Into an object...

{
groupA: ['a', 'b', 'c'],
groupB: ['a', 'd', 'f']
}

The plain text data will vary in length, but the structure will always be represented like:

[parent group]
child item 1
child item 2
...

CodePudding user response：

You can use split and reduce

const string = `[group a]
a
b
c
[group b]
a
d
f`

const list = string.split(`\n`)
let saveKey;
const obj = list.reduce((acc,cur) => {
  if (cur.startsWith('[')) { 
    const groupLetter = cur.match(/ (\w )\]/)[1].toUpperCase()

    saveKey = `group${groupLetter}`;
    acc[saveKey]=[];
  }  
  else {
    acc[saveKey].push(cur);
  }  
  return acc
},{})
console.log(obj)

CodePudding user response：

You can grab all the lines of text and reduce the lines by parsing and determining if it is a key or a value. Your accumulator needs to store both the results and the current key.

const
  parse = (text) =>
    text.trim().split('\n')
    .reduce((acc, line) => {
      const match = line.trim().match(/^\[(. )\]$/);
      return match
        ? { ...acc, key: match[1] }
        : { ...acc, result: { ...acc.result,
            [acc.key]: [...(acc.result[acc.key] ?? []), line.trim()] }
          };
    }, { result: {}, key: null }).result,
  data = parse(document.querySelector('#data').value);

console.log(data);

.as-console-wrapper { top: 0; max-height: 100% !important; }

#data { display: none; }

<textarea id="data">[group a]
a
b
c
[group b]
a
d
f</textarea>

CodePudding user response：

Make an array of the original string by splitting on \n, then loop through and create the object:

const str = `[group a]
a
b
c
[group b]
a
d
f`

const arr = str.split('\n')
const obj = {}
let curHeader

arr.forEach(el =>
{
  if(el[0] === '[')
  {
    let frmtEl = el.substring(1, el.length-1)
    let frmtElArr = frmtEl.split(' ')
    curHeader = frmtElArr[0]   frmtElArr[1].toUpperCase()
    obj[curHeader] = []
  }
  else
  {
    obj[curHeader].push(el)
  }
})

console.log(obj)

CodePudding user response：

(1) Start off by split()ting with [ as the separator which should give you as many groups as there are in the string:

[ '', 'group a]\na\nb\nc\n', 'group b]\na\nd\nf' ]

(2) Use .filter() to remove undesired empty strings:

[ 'group a]\na\nb\nc\n', 'group b]\na\nd\nf' ]

(3) Now use .map() to transform each group using ] or \n as separators:

[ [ 'group a', '', 'a', 'b', 'c', '' ], [ 'group b', '', 'a', 'd', 'f' ] ]

(4) Use .filter() to remove undesired empty strings:

[ [ 'group a', 'a', 'b', 'c' ], [ 'group b', 'a', 'd', 'f' ] ]

(5) Lastly use .reduce() and Object.assign() to convert each group into a key-value pair:

{ 'group a': [ 'a', 'b', 'c' ], 'group b': [ 'a', 'd', 'f' ] }

Please note that the fragment,

.split(' ').map((a,i) => i === 0 ? a : a.toUpperCase()).join('')

is what converts group a into groupA, etc

DEMO

let data = `[group a]
a
b
c
[group b]
a
d
f
[group c]
g
h
t`;

let obj = data
          .split(/\[/)
          .filter(v => v) 
          .map(v => v.split(/\]|[\r\n] /)
          .filter(v => v))
          .reduce((acc,val) => 
              Object.assign(acc,
                {[val[0].split(' ').map((a,i) => i === 0 ? a : a.toUpperCase()).join('')]:val.slice(1)}),{});

console.log( obj );