Reusable transformers

Reusable transformers are functions that can be registered when creating a schema builder. They can then be used to transform values with the transform property of a column, simply by referencing the function name.

const schema = ExcelSchemaBuilder.create<{ firstName: string, lastName: string, countries: string[] }>()
  .withTransformers({
    uppercase: (value: string) => value.toUpperCase(),
    lowercase: (value: string) => value.toLowerCase(),
    listArray: (value: string[]) => value.join(', '),
    listArrayUppercase: (value: string[]) => value.map(v => v.toUpperCase()).join(', '),
  })
  .column('firstName', { key: 'firstName', transform: 'uppercase' })
  .column('lastName', { key: 'lastName', transform: 'lowercase' })
  .column('countries', { key: 'countries', transform: '
' })

Reusable Transformers

You can also define reusable transformers that can be used across multiple schemas :

import { ExcelSchemaBuilder } from '@chronicstone/typed-xlsx'

const transformers = {
  uppercase: (value: string) => value.toUpperCase(),
  lowercase: (value: string) => value.toLowerCase(),
  listArray: (value: string[]) => value.join(', '),
} as const

const schema = ExcelSchemaBuilder.create<{ firstName: string, lastName: string, countries: string[] }>()
  .withTransformers(transformers)
  .column('firstName', { key: 'firstName', transform: 'uppercase' })
  .column('lastName', { key: 'lastName', transform: 'lowercase' })
  .column('countries', { key: 'countries', transform: 'listArray' })