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x/ramda/source/descend.js

:ram: Practical functional Javascript
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import _curry3 from './internal/_curry3.js';

/** * Makes a descending comparator function out of a function that returns a value * that can be compared with `<` and `>`. * * @func * @memberOf R * @since v0.23.0 * @category Function * @sig Ord b => (a -> b) -> a -> a -> Number * @param {Function} fn A function of arity one that returns a value that can be compared * @param {*} a The first item to be compared. * @param {*} b The second item to be compared. * @return {Number} `-1` if fn(a) > fn(b), `1` if fn(b) > fn(a), otherwise `0` * @see R.ascend * @example * * const byAge = R.descend(R.prop('age')); * const people = [ * { name: 'Emma', age: 70 }, * { name: 'Peter', age: 78 }, * { name: 'Mikhail', age: 62 }, * ]; * const peopleByOldestFirst = R.sort(byAge, people); * //=> [{ name: 'Peter', age: 78 }, { name: 'Emma', age: 70 }, { name: 'Mikhail', age: 62 }] */var descend = _curry3(function descend(fn, a, b) { var aa = fn(a); var bb = fn(b); return aa > bb ? -1 : aa < bb ? 1 : 0;});export default descend;