castr

Cast value to any type

import * as castr from 'castr'

castr.toNumber('1') // 1

View cheat sheet

String

Turn any value into a string (cheat sheet)

castr.toString('hello') // "hello"

function toString(value: any, options: Options = {}): string

interface Options {
  false?: string
  null?: string
  parse?: boolean
  true?: string
  undefined?: string
}

Cases

If you pass a number, it will be converted to a string:

castr.toString(-42.5) // "-42.5"

undefined or null are translated into empty strings:

castr.toString(undefined) // ""
castr.toString(null) // ""

You can overwrite this by passing a custom string:

castr.toString(undefined, { undefined: 'missing' }) // "missing"
castr.toString(null, { null: 'ignored' }) // "ignored"

Booleans are stringified like this:

castr.toString(true) // "true"
castr.toString(false) // "false"

You can also owerwrite this:

castr.toString(true, { true: 'yes' }) // "yes"
castr.toString(false, { false: 'no' }) // "no"

If you pass a plain object as a JSON string, it will be parsed:

castr.toString({ foo: 1 }) // "{\"foo\": 1}"

You can also overwrite this:

castr.toString({ foo: 1 }, { parse: false }) // "[object Object]"

In case you pass an instantiated class, the method toString will be called on it:

castr.toString(new Error('foo')) // "Error: foo"

Arrays are joined with a comma:

castr.toString([1, 2, 3]) // "1,2,3"
castr.toString([]) // ""

You can force the array to be stringified as JSON:

castr.toString([1, 2, 3], { parse: true }) // "[1,2,3]"
castr.toString([], { parse: true }) // "[]"

Number

Turn any value into a number (cheat sheet)

castr.toNumber(22) // 22

function toNumber(value: any, options: Options = {}): string

interface Options {
  Infinity?: number
  NaN?: number
  count?: boolean
}

Cases

In case the value can not be casted to a number, it will return 0 unless specified otherwise

castr.toNumber(null) // 0
castr.toNumber(null, { NaN: -1 }) // -1
castr.toNumber(Infinity, { Infinity: -1 }) // -1

If the value is a numeric string, it will be casted to a number

castr.toNumber('-1.5') // -1.5

Booleans value are represented as numbers:

castr.toNumber(true) // 1
castr.toNumber(false) // 0

Cast will return lenght if possible:

castr.toNumber('abc') // 3
castr.toNumber([1, 2, 3]) // 3
castr.toNumber({ foo: 1, bar: 2 }) // 2

Use count to overwite this

castr.toNumber('abc', { count: false }) // 0