Javascript array value compare

Question

I am checking each checkbox status (2 elements in total).

var checked = [];
document.querySelectorAll('.checkbox').forEach(function(e,i){
 checked.push(e.checked)
})

Now checked value could be

(2) [true, true]

or

(2) [true, false]

or

(2) [false, true]

or

(2) [false, false]

I am now checking it with a little bit manual way

if(checked[0] && check[1]) { ... }

If I have more elements, I have to add them manually like

 if(checked[0] && check[1] && check[2]) { ... }

I am seeking a better way to polish my code, so I don't need to manually add array values to compare. Thanks

You want to check if all are true or not?

gurvinder372
– gurvinder372

2018-04-04 11:30:58 +00:00
Commented Apr 4, 2018 at 11:30 — gurvinder372
– gurvinder372, Commented Apr 4, 2018 at 11:30
Yes, I'd like to check if all true

olo
– olo

2018-04-04 11:31:43 +00:00
Commented Apr 4, 2018 at 11:31 — olo
– olo, Commented Apr 4, 2018 at 11:31

gurvinder372 · Accepted Answer · 2018-04-04 11:32:27Z

5

Use every and Array.from

var checked = [];
var allCheckboxes = document.querySelectorAll('.checkbox');
var allChecked = Array.from( allCheckboxes ).every( s => s.checked )

answered Apr 4, 2018 at 11:32

gurvinder372

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3 Comments

olo Over a year ago

ah! yes! every Thank you very much

olo Over a year ago

just checked developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… IE doesnt support from Is there a way to support IE and some mobile browsers ? Thanks

gurvinder372 Over a year ago

@olo You can use every's pollyfil developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…

3Dos · Accepted Answer · 2018-04-04 11:36:10Z

0

You can use Array.reduce to do that like this

const pass = [true, true, true]
const passNot = [true, false, true]

const reducer = (isPassing, value) => {
  if (value === false) return false
  else return isPassing
}

console.log('yay', pass.reduce(reducer, true))
console.log('nay', passNot.reduce(reducer, true))

answered Apr 4, 2018 at 11:36

3Dos

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1 Comment

olo Over a year ago

This method supports IE and most of mobile browsers! Many thanks!

Jason · Accepted Answer · 2018-04-04 11:38:47Z

0

You are tryng to combine an array of values into a single one, thats what the reduce method does.

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

    let result = document.querySelectorAll('.checkbox')
    .map( box => box.checked ) // get an array of boolean
    .reduce ( (bool, res) => return bool && res /*all checkboxes must be checked */, true /* initial value */ );

answered Apr 4, 2018 at 11:38

Jason

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