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Diffstat (limited to 'node_modules/fbjs/lib/minBy.js.flow')
-rw-r--r-- | node_modules/fbjs/lib/minBy.js.flow | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/node_modules/fbjs/lib/minBy.js.flow b/node_modules/fbjs/lib/minBy.js.flow new file mode 100644 index 000000000..a76aec4fa --- /dev/null +++ b/node_modules/fbjs/lib/minBy.js.flow @@ -0,0 +1,37 @@ +/** + * Copyright (c) 2013-present, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under the BSD-style license found in the + * LICENSE file in the root directory of this source tree. An additional grant + * of patent rights can be found in the PATENTS file in the same directory. + * + * @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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