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/**
* Copyright (c) 2013-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @providesModule minBy
* @flow
*/
var compareNumber = (a, b) => a - b;
/**
* Returns the minimum element as measured by a scoring function f. Returns the
* first such element if there are ties.
*/
function minBy<A, B>(as: Iterable<A>, f: (a: A) => B, compare?: ?(u: B, v: B) => number): ?A {
compare = compare || (compareNumber: any);
var minA = undefined;
var minB = undefined;
var seenFirst = false;
for (var a of as) {
var b = f(a);
if (!seenFirst || compare(b, (minB: any)) < 0) {
minA = a;
minB = b;
seenFirst = true;
}
}
return minA;
}
module.exports = minBy;
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