number.ts

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

/**
 * A number. By default reject NaN and Infinity values.
 *
 * Options:
 *
 *   allowNaN .. allow NaN values
 *   allowInfinity .. allow positive and negative Infinity values
 *   min .. reject numbers smaller than that
 *   max .. reject numbers larger than that
 */
export function number(options?: {
  allowNaN?: boolean
  allowInfinity?: boolean
  min?: number
  max?: number
}): Runtype<number> {
  const { allowNaN, allowInfinity, min, max } = options || {}

  return setupInternalRuntype<number>(
    (v, failOrThrow) => {
      if (typeof v !== 'number') {
        return createFail(failOrThrow, 'expected a number', v)
      }

      if (!allowNaN && isNaN(v)) {
        return createFail(failOrThrow, 'expected a number that is not NaN', v)
      }

      if (!allowInfinity && (v === Infinity || v === -Infinity)) {
        return createFail(failOrThrow, 'expected a finite number', v)
      }

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

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

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