Typescripting Twitter snippets part 1

typescripting-twitter-snippets-part1.ts

/*************************************************************
 * https://twitter.com/marcelcruz/status/1282005231065341953 *
 *************************************************************/

/**
 * original js
 */
const capitalize = ([firstLetter, ...rest]) => {
  return firstLetter.toUpperCase() + rest.join('')
}

/**
 * typescript
 */
const capitalize = ([firstLetter, ...rest]: string) => {
  return firstLetter.toUpperCase() + rest.join('')
}

/**********************************************************************
 * https://twitter.com/gustavo_pch/status/1282121799749296128/photo/1 *
 **********************************************************************/

 /**
 * some types for context that I wrote, not sure if correct
 */

type Query = string[]

type ViewsDefinition = {
  foo: {
    queries: Query
  },
  bar: {
    queries: Query
  }
}

const application = {
  views: {
    foo: {
      queries: ['queries'],
    },
    bar: {
      queries: ['queries'],
    },
  },
}

/**
 * original ts
 */

const views = Object.entries(application.views).reduce(
  (acc, [viewName, view]) => {
    acc[viewName as keyof ViewsDefinition] = view.queries
    return acc
  },
  {} as {
    [viewName in keyof ViewsDefinition]: ViewsDefinition[viewName]['queries']
  }
)

/**
 * typescript
 */

const views = Object.entries(application.views).reduce<Record<keyof ViewsDefinition, Query>>(
  (acc, [viewName, view]) => {
    acc[viewName] = view.queries
    return acc
  },
  {} as Record<keyof ViewsDefinition, Query>
)

/**
 * How does record work?
 */

 type Obj = { [key: string]: boolean }
 type SameObj = Record<string, boolean>