Rense Bakker

Mapping Records to arrays

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Rense Bakker
·

1 min read

I needed this functionality to parse a configuration regardless of whether it was supplied as an array or a Record. This function converts the Record into an array of the same type:

function mapRecordToArray<T, R extends Omit<T, K>, K extends keyof T>(record: Record<string, R>, recordKeyName: K) {
  return Object.keys(record).map(key => ({ ...record[key as keyof typeof record], [recordKeyName]: key })) as T[]
}

It can be used like this:

type Field = {
  name: string,
  label: string,
}

type Collection = {
  name: string,
  label: string,
  fields: Record<string, Omit<Field, 'name'>> | Field[]
}

const collections:Collections[] = [] // ...

function getFields(){
  return collections.map(collection => {
    const fields = Array.isArray(collection.fields)
      ? collection.fields
      : mapRecordToArray(collection.fields, 'name')
  })
}
// Function return type will be Field[]
TypeScript