Is there a "all" or "any" operator for boolean lists in typescript

Question

I want to write an if statement of the form

if (all entries in booleanList are true) {do something}

Just putting in the booleanList does the equivalent of .any()

I could not find an answer on the internet or in a typescript book. Thanks in advance for any help.

Timecard

Answer 1

Sure, it's every:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every

const list = [true, false, true];

const every = list.every(bool => bool === true); // false
// const every = list.every(bool => bool); // false

Myxomycete

thank you I'm going to accept @Eras answer since he was the fastest. – Timecard

@Eras was actually the slowest :D – Amatol

for me it says 13 for him and 12 for the other 2 – Timecard

Answer 2

Typescript compiles to Javascript, so it doesn't have any features available at runtime that Javascript doesn't have. However, Javascript does have both every and some since ES5, so long as you pass an identity function:

arr.every(x => x) // all
arr.some(x => x)  // any

This kind of thing is unlikely to be documented in Typescript books specifically, because there would be no need to duplicate the contents of a Javascript book just to say that Typescript has those features too. If you want to know what functions are available in the standard library, you should consult a Javascript reference, such as the MDN Javascript reference.

Eras

Answer 3

You could use the Array.prototype.every() function for that:

if(booleanList.every(val => val)){
 do something
}

Generality

thank you I'm going to accept @Eras answer since he was the fastest. – Timecard

if by fastest, you mean answered last, sure, but that's not what that word means. have my upvote, on account of being fasted. – Concerted