@webframe/utils

Small helpers for any JavaScript runtime: Node, browsers, workers.

npm install @webframe/utils

assertUnreachable

Marks code that can't be reached, such as the default of a switch that covers every case. If a case is added later and not handled, TypeScript reports it; if it's reached anyway at runtime, it throws. It comes from @webframe/assert-unreachable, for code that needs only it.

import { assertUnreachable } from '@webframe/utils'

type Status = 'active' | 'suspended'

function label(status: Status) {
  switch (status) {
    case 'active': return 'Active'
    case 'suspended': return 'Suspended'
    default: return assertUnreachable(status, `Unknown status: ${status}`)
  }
}

normaliseEmailAddress

Trims an email address, puts it in lower case, and removes a +tag, so one inbox is one account.

normaliseEmailAddress('  Ada+news@Example.com ') // 'ada@example.com'

updateJSON

Sets a value at a dot path in a JSON string, making any objects on the way. It's handy for small preferences kept as JSON in a cookie.

updateJSON('{"menu":{}}', 'menu.open', true)  // '{"menu":{"open":true}}'
updateJSON('', 'a.b', 1)                      // '{"a":{"b":1}}'

Paths containing __proto__, prototype or constructor throw, so a path taken from a request can't alter every object in the program.