var baseSetData = require('./_baseSetData'), now = require('./now'); /** Used to detect hot functions by number of calls within a span of milliseconds. */ var HOT_COUNT = 150, HOT_SPAN = 16; /** * Sets metadata for `func`. * * **Note:** If this function becomes hot, i.e. is invoked a lot in a short * period of time, it will trip its breaker and transition to an identity * function to avoid garbage collection pauses in V8. See * [V8 issue 2070](https://bugs.chromium.org/p/v8/issues/detail?id=2070) * for more details. * * @private * @param {Function} func The function to associate metadata with. * @param {*} data The metadata. * @returns {Function} Returns `func`. */ var setData = (function() { var count = 0, lastCalled = 0; return function(key, value) { var stamp = now(), remaining = HOT_SPAN - (stamp - lastCalled); lastCalled = stamp; if (remaining > 0) { if (++count >= HOT_COUNT) { return key; } } else { count = 0; } return baseSetData(key, value); }; }()); module.exports = setData;