import { curryN, map, range, always } from 'ramda'; import floor from './floor'; /** * Creates an array of numbers (positive and/or negative) progressing from start up to, but not including, end. * * `Note`: JavaScript follows the IEEE-754 standard for resolving floating-point values which can produce unexpected results. * * @func rangeStep * @memberOf RA * @category List * @since {@link https://char0n.github.io/ramda-adjunct/2.30.0|v2.30.0} * @sig Number -> Number -> Number -> [Number] * @param {number} step The value to increment or decrement by * @param {number} from The start of the range * @param {number} to The end of the range * @return {number[]} Returns the range of numbers * @see {@link http://ramdajs.com/docs/#range|R.range} * @example * * RA.rangeStep(1, 0, 4); // => [0, 1 ,2, 3] * RA.rangeStep(-1, 0, -4); // => [0, -1, -2, -3] * RA.rangeStep(1, 1, 5); // => [1, 2, 3, 4] * RA.rangeStep(5, 0, 20); // => [0, 5, 10, 15] * RA.rangeStep(-1, 0, -4); // => [0, -1, -2, -3] * RA.rangeStep(0, 1, 4); // => [1, 1, 1] * RA.rangeStep(1, 0, 0); // => [] */ const rangeStep = curryN(3, (step, from, to) => { const callback = step === 0 ? always(from) : (n) => from + step * n; const rangeEnd = step === 0 ? to - from : floor((to - from) / step); return map(callback, range(0, rangeEnd)); }); export default rangeStep;