1. new Date().getTime()
new Date().getTime(); //1619167642040
2. Date.now()
Date.now(); //1619167705466
3. new Date() - 0
new Date() - 0; // 1619167777211
4. Date.parse(new Date())
Date.parse(new Date()); //1619167844000
5. +new Date()
+new Date(); //1619167926401
6. new Date().valueOf()
new Date().valueOf(); //1619168001786
7. Number(new Date())
Number(new Date()); // 1619168068132
