It is difficult for human eyes to parse long numeric literals quickly.
let total_limit = 1000000000000; //What's this? A billion? 100 million? 1 trillion? Confusing.
This can be written with numeric separators like..
let total_limit = 1_000_000_000_000; //So this is 1 trillion. Easily readable with the numeric separators.
Let’s see more examples.
const price = 74_99; // 74 dollars and 99 cents. const color = 0xA3_3A_3A; // Color code in hex treated as three bytes. let fraction = 0.00_1; //One thousanth. let nibbles = 0b1010_0101_1100_1101; //binary nibbles