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/** | |
* useScroll React custom hook | |
* Usage: | |
* const { scrollX, scrollY, scrollDirection } = useScroll(); | |
*/ | |
import { useState, useEffect } from "react"; | |
export function useScroll() { | |
const [lastScrollTop, setLastScrollTop] = useState(0); |
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//Primitive Type Comparison | |
var a = 1; | |
var b = 1; | |
var c = a; | |
console.log(a == b); //true | |
console.log(a === b); //true | |
console.log(a == c); //true | |
console.log(a === c); //true |
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Latency Comparison Numbers (~2012) | |
---------------------------------- | |
L1 cache reference 0.5 ns | |
Branch mispredict 5 ns | |
L2 cache reference 7 ns 14x L1 cache | |
Mutex lock/unlock 25 ns | |
Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
Compress 1K bytes with Zippy 3,000 ns 3 us | |
Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |