1. You can use
You can also use e notation.
3. Always use triple equal,
===, to compare the value and type when comparing values.
toFixed() to convert a number to a string and round to a fixed number of decimals.
slice() will let you truncate an array.
How to remove duplicates in an Array using ES 2015
How to improve your image performance
By following these steps you can improve the image performance on your site, which should improve the experience for your visitors and give you a better PageSpeed score.