JavaScript: a useful true or false function
Blogs20142014-11-12
JavaScript: a useful true or false function
Sometimes in J judge true of false is tricky. I wrote a function to easily check a boolean express to return true or false. It is useful in a complex condition judge.
//define it if not exists:
if(!Array.prototype.trueOrFalse) {
Array.prototype.trueOrFalse = function() {
return this
.forEach(function(obj) {
if(!!obj) {
console.log(obj + ': true');
return true;
}
else {
console.log(obj + ': false');
return false;
}
});
}
}
//then:
[[],{},undefined,null,'',false,true].trueOrFalse();
//true,true,false,false, false, false,true
[true && false].trueOrFalse(); //false
[true || false].trueOrFalse(); //true
[!'' || ![]].trueOrFalse(); //true
[!'' && ![]].trueOrFalse(); //false
[!null || !undefined].trueOrFalse(); //true
[!null && !undefined].trueOrFalse(); //true
...It is interesting, and can extend to whatever you want.