Option columns_duplicates_to_array

When activated by settings its value to true, the columns_duplicates_to_array option will convert the return values into arrays of values when multiple columns of the same name are found.

The option implies the usage of the columns mode where records are returned as literal objects. An error is thrown if the columns mode is not activated.

• Type: boolean
• Optional
• Default: false (a one character comma)
• Since: 0.0.1
• Related: columns — see Available Options

Example

The columns_duplicates_to_array example contains a CSV data set with two columns named "email". Without the columns_duplicates_to_array option, only the last email will be available. Instead, every email is returned in the form of an array:

const parse = require('csv-parse')
const assert = require('assert')

parse(`
friend,username,friend
athos,porthos,aramis
porthos,d_artagnan,athos
`.trim(), {
  columns: true,
  columns_duplicates_to_array: true
}, function(err, records){
  assert.deepStrictEqual(
    records, [{
      username: 'porthos',
      friend: ['athos', 'aramis']
    }, {
      username: 'd_artagnan',
      friend: ['porthos', 'athos']
    }]
  )
})