CODEWITHSUNDEEP
javascript
3355307
3355307

Reputation: 1678

Better way to check multiple OR condition within single if statement in javascript

Is it possible to further simplify the following javascript statement. the requirement is if any input is negative it should execute the statement inside if block. i am wondering if i can avoid < 0 multiple times and just use once

    if (Number(cash.value) < 0 || Number(cheque.value) < 0 || Number(charge.value) < 0 || Number(card.value) < 0) {
doSomething();
}

i simplified to this logic

if ((Number(Cash.value) || Number(Cheque.value) || Number(Charge.value) || Number(Card.value)) < 0)

but it does not work and does not meet requirement. the above logic works but there is duplication of <0 logic

Upvotes: 0

Views: 120

Answers (5)

user1693593
user1693593

Reputation:

You can simplify removing for example Number() - the + sign turns strings holding a number into an actual number, and we can still use the faster logic operands:

if (+cash.value < 0 || +cheque.value < 0 || +charge.value < 0 || +card.value) < 0) {
  doSomething();
}

As to the problem with the second line -

The reason this line doesn't work (besides from a possible typo, as JavaScript is case-sensitive):

if ((Number(Cash.value) || Number(Cheque.value) || Number(Charge.value) || Number(Card.value)) < 0)

is that this Number(Cash.value) is converted into a boolean value, ie. if the value is 0 then false, anything else will convert to true. So if the numbers are non-0, plus or minus, they will pass through, except the last test which only passes as intended. Each value has to be tested individually.

Word of advice: unless you need to check numerous values in parallel, avoid using arrays (whether its ES6 or earlier). This is significantly slower than doing boolean checks directly, especially in older browsers which parses and have no optimization of JavaScript.

Upvotes: 2

Suren Srapyan
Suren Srapyan

Reputation: 68685

You can try to do like this

var numbers = [Cash.value, Cheque.value, Charge.value, Card.value];

if(numbers.some(value => Number(value) < 0)){
   doSomething();
}

For Example, is working in ES6

var numbers = [11, 12, -1,-7];

if(numbers.some(value => value < 0)){
   console.log('Found !!!');
}

For under IE 9, you can write a function and use 

function anyNegative(numbers){
  for(var i = 0; i < numbers.length; i++){
     if(numbers[i] < 0){
        return true;
     }
  }
  
  return false;
}

var numbers = [11, 12, -1,-7];

if(anyNegative(numbers)){
     console.log('Found !!!');
}

Upvotes: 6

stefanos
stefanos

Reputation: 270

How about :

if([Cash,Cheque,Charge,Card].some(obj => Number(obj.value) < 0)) {
    doSomething();
}

Upvotes: 0

Dan
Dan

Reputation: 670

I think, not really.

Your second statement will not work, because you are essentially checking all the values - except for the last one - to be truthy, and then only the last one for being negative.

If you want to make the code more readable, you might add a helper function:

function isNegative(value) {
  return Number(value) < 0;
}

And then use that in your if statements.

Technically you could make a function like this:

function atLeastOneNegative() {
  for (var i = 0; i < arguments.length; i++) {
    if (Number(i) < 0) return true;
 } 

  return false;
}

But I think the first option would give nicer code.

Upvotes: 0

Andreas Turku
Andreas Turku

Reputation: 413

Or have it as a function, in case you need it in more places. It takes N number of inputs to verify

https://jsfiddle.net/2L1L7ncj/

function isAnyArgumentNegative(){
    var args = Array.prototype.slice.call(arguments);
  return args.some(function(a){
    return Number(a) < 0;
  });
}

Upvotes: 0

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