import { isNil } from '../is'
/**
* Generate an integer Array containing an arithmetic progression. A port of
* the native Python `range()` function. See
* [the Python documentation](http://docs.python.org/library/functions.html#range).
*
* @name range
* @since 5.0.0-beta.6
* @memberOf math
*
* @param {number} start starting number
* @param {number} [stop] ending number, defaultsTo(start)
* @param {number} [step] step, defaultsto(-1 || 1)
* @return {Array<number>} [start...stop]
*
* {@link https://github.com/jashkenas/underscore/blob/master/underscore.js#L714 underscore-range}
* @see {@link underscore-range}
*
* @example
*
* range(10)
* //=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
* range(1, 11)
* //=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
* range(0, 30, 5)
* //=> [0, 5, 10, 15, 20, 25]
* range(0, -10, -1)
* //=> [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
* range(0)
* //=> []
*
*/
export default function range(start: number, stop?: number, step?: number) {
if (isNil(stop)) {
stop = start || 0
start = 0
}
if (!step) {
step = stop < start ? -1 : 1
}
const length = Math.max(Math.ceil((stop - start) / step), 0)
const result = new Array(length)
for (let idx = 0; idx < length; idx++, start += step) {
result[idx] = start
}
return result
}