integer.ts

import {
  createFail,
  InternalRuntype,
  isFail,
  propagateFail,
  Runtype,
  setupInternalRuntype,
} from './runtype'

export const integerRuntype = setupInternalRuntype<number>(
  (v, failOrThrow) => {
    if (typeof v === 'number' && Number.isSafeInteger(v)) {
      return v
    }

    return createFail(failOrThrow, 'expected a safe integer', v)
  },
  { isPure: true },
)

/**
 * A Number that is a `isSafeInteger()`
 *
 * Options:
 *
 *   min .. reject numbers smaller than that
 *   max .. reject number larger than that
 */
export function integer(options?: {
  max?: number
  min?: number
}): Runtype<number> {
  if (!options) {
    return integerRuntype
  }

  const { min, max } = options

  return setupInternalRuntype<number>(
    (v, failOrThrow) => {
      const n = (integerRuntype as InternalRuntype<number>)(v, failOrThrow)

      if (isFail(n)) {
        return propagateFail(failOrThrow, n, v)
      }

      if (min !== undefined && n < min) {
        return createFail(
          failOrThrow,
          `expected the integer to be >= ${min}`,
          v,
        )
      }

      if (max !== undefined && n > max) {
        return createFail(
          failOrThrow,
          `expected the integer to be <= ${max}`,
          v,
        )
      }

      return n
    },
    { isPure: true },
  )
}