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comparator.js
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comparator.js
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import _curry1 from './internal/_curry1.js';
/**
* Makes a comparator function out of a function that reports whether the first
* element is less than the second.
*
* @func
* @memberOf R
* @since v0.1.0
* @category Function
* @sig ((a, b) -> Boolean) -> ((a, b) -> Number)
* @param {Function} pred A predicate function of arity two which will return `true` if the first argument
* is less than the second, `false` otherwise
* @return {Function} A Function :: a -> b -> Int that returns `-1` if a < b, `1` if b < a, otherwise `0`
* @example
*
* const byAge = R.comparator((a, b) => a.age < b.age);
* const people = [
* { name: 'Emma', age: 70 },
* { name: 'Peter', age: 78 },
* { name: 'Mikhail', age: 62 },
* ];
* const peopleByIncreasingAge = R.sort(byAge, people);
* //=> [{ name: 'Mikhail', age: 62 },{ name: 'Emma', age: 70 }, { name: 'Peter', age: 78 }]
*/
var comparator = _curry1(function comparator(pred) {
return function(a, b) {
return pred(a, b) ? -1 : pred(b, a) ? 1 : 0;
};
});
export default comparator;