diff --git a/blog_posts/javascript-numeric-separator.md b/blog_posts/javascript-numeric-separator.md new file mode 100644 index 000000000..ffee778c1 --- /dev/null +++ b/blog_posts/javascript-numeric-separator.md @@ -0,0 +1,29 @@ +--- +title: JavaScript's numeric separators explained +type: story +tags: javascript,math,type +authors: chalarangelo +cover: blog_images/coffee-drip.jpg +excerpt: Numeric separators are a somewhat lesser-known JavaScript syntactic sugar that can make working with large constants a lot easier. +firstSeen: 2021-06-27T05:00:00-04:00 +--- + +Numeric separators are a lesser-known JavaScript syntactic sugar that can make working with numeric constants a lot easier. The long and short of it is that you can add underscores (`_`) to numeric values to make them more readable. + +The idea of separating large numeric values with a special character might sound familiar on account of it being a syntax present in multiple other languages, such as Java, Python, Ruby etc. From what I can tell, numeric separators are at their best when creating shared constants that will not change and are very large, have many repeated digits and/or can be ambiguous. + +Apart from readability, numeric separators don't really offer anything else. For the sceptics among us that don't really see a lot of readability value either, I'd like to show two rather convincing sample cases: + +```js +// How many zeroes is that? Millions? Billions? Trillions? +const msInOneYear = 31536000000; +// Is this 4,200 or 42.00 (in cents)? +const price = 4200; + +// Ok, this is approximately 31.5 billion +const msInOneYear = 31_536_000_000; +// Based on the separator, this should be 42.00 (cents) +const price = 42_00; +``` + +Finally, as far as caveats go, you only need to remember that numbers cannot start or end with a numeric separator and that you can't have two or more numeric separators in a row.