iter-tools-es/impls/$slice/internal/validate-args.js

The iterable toolbox

const {
  isInteger,
  isPositiveInteger,
  isIntegerOrInfinite
} = require('../../../internal/number.js');

const {
  isObject
} = require('../../is-object/is-object.js');

const makeValidateArgs = methodName => function validateArgs(args) {
  let [, optsOrStart = 0, end = Infinity, step = 1] = args;
  let start = typeof optsOrStart === 'number' ? optsOrStart : undefined;

  if (isObject(optsOrStart)) {
    ({
      start = 0,
      end = Infinity,
      step = 1
    } = optsOrStart);
  }

  if (!isInteger(start)) {
    throw new TypeError(`start argument to ${methodName} must be a number`);
  }

  if (!isIntegerOrInfinite(end)) {
    throw new TypeError(`end argument to ${methodName} must be an integer or infinte`);
  }

  if (!isPositiveInteger(step)) {
    throw new TypeError(`step argument to ${methodName} must be a integer > 0`);
  }

  args[1] = start;
  args[2] = end;
  args[3] = step;
};

exports.makeValidateArgs = makeValidateArgs;