Is there an equivalent of "Array.None" in JS?

Question

There's a similar question for LINQ: Is there an equivalent of None() in LINQ?

There are some boolean methods on collections / arrays:

• Array.some (similar to linq.Any)
• Array.every (similar to linq.All)

Can I check if no elements in array match a given function callback

A possible workaround is to .filter and then check .length and make sure it's zero:

let arr = ["a","b","c"]
// make sure that no item in array = "b"
let noBs = arr.filter(el => el === "b").length === 0

Answer 1

As logically concluded by the linq example

None is the same as !Any, so you could define your own extension method as follows:

let none = (arr, callback) => !arr.some(callback)

And then call like this:

let arr = ["a","b","c"]
let noBs = none(arr, el => el === "b")

---

Or if you want to extend Array.proto, you can add the following method:

Object.defineProperty(Array.prototype, 'none', {
    value: function (callback) { return !this.some(callback) }
});

Then call like this:

let arr = ["a","b","c"]
let noBs = arr.none(el => el === "b")

Answer 2

Not at the moment

At the moment I'm using an Array.some() and then negating the whole thing

Personally I think an Array.none function would be awesome

You could request it to be added to the next release of ECMA. It looks like a bit of a process to say the least but if we wanted to get this added to ECMA this would be the way.