I have an instance where arrays of potentially different length can look like this...
Array [ true, false, false, true ]
Or
Array [ true, true, true, false, true ]
Or
Array [ true, true, true ]
I need to iterate through an array and ONLY trigger a new event if there is ONE instance of "false".
Out of sample arrays I presented,, this one wold be the only one that is valid
Array [ true, true, true, false, true ]
What would be the least elaborate way to accomplish this?
You could do it by using Array.filter
var arr = [ true, true, true, false, true ];
if(arr.filter(function(b){ return !b; }).length == 1){
// trigger the event
}
The above filters to just contain Array of false and then we check if the length of that Array is 1
Another creative way of doing this might be using replace and indexOf, where you're just replacing the first occurrence of false in a String formed by joining the arr and checking if there are still any false in the string and negate it with ! operator to achieve the results.
if(!(arr.join("").replace("false","").indexOf("false") > -1)){
// trigger
}
Amit Joki already has a working answer, but I'd just like to share another solution using reduce:
var count = arr.reduce(function(prevVal, currVal) {
return prevVal + (!currVal ? 1 : 0);
}, 0);
if (count === 1) {
// Do something
}
