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
As logically concluded by the linq example: None is the same as !Any, so you could define your own utility method like this:
const none = (arr, callback) => !arr.some(callback)
And then call like this:
const arr = ["a","b","c"]
const hasNoCs = none(arr, el => el === "c") // false
const hasNoDs = none(arr, el => el === "d") // true
const none = (arr, callback) => !arr.some(callback)
const arr = ["a","b","c"]
const hasNoCs = none(arr, el => el === "c") // false
const hasNoDs = none(arr, el => el === "d") // true
console.log({hasNoCs, hasNoDs})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.
not every is not the same as none!
Array.some (to my knowledge there's no any alias in JS).
!Array.some(...) will be true when every entry is falsy, and false otherwiseLiked the @KyledMit approach. On the similar lines, using the findIndex is another way. (find may not be reliable as we can not check on return value).
const arr = ["a","b","c"]
const noBs = arr.findIndex(el => el === "b") < 0;
console.log(noBs)