What is the meaning of an Underscore in javascript function parameter?

Question

I was going through the code of one of the chart library written in javascript, wherein I\'ve seen passing underscore(_) as a function parameter. What does that mean?

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Answer 1

_ in fat arrow function is called as throwaway variable. It means that actually we're creating an variable but simply ignoring it. More devs are now a days using this as syntactic sugar or short hand while writing code, as it's easy and one character less to write the code.

Instead of using _, you can use other variables like temp, x, etc

for examples:

() => console.log('Hello World')



_ => console.log('Hello World')




x => console.log('Hello World')

But personally i prefer to use () type over throwaway variable if no arguments are needed.

See the following code, then you will understand it better.

_ as an argument,

  f = _=> {
    return _ + 2 ;
}

f(3) will return 5

For better understanding, check wes bos