Function not console logging when called by other function

Question

I have 2 functions on a single .js file.

function notUsed(id) {
        //default to false because if true then id not being used and good for new user
        var notInUse = false;

        console.log(notInUse);
        return !notInUse;   
    }

function generateID() {

        //number of zeros represents the number of digits in id code
        const SIZEOFID = 10000000;
        const ID_DIGITS = 7;
        //letter to start id for non los rios people
        const STRTOFID = "C";
        //variable to hold finished id code & variable to hold 7 digit of id code
        var id, idNum;

        //loop to make sure id contains 7 digits and 1 letter and not used already
        do {
            idNum = Math.round(Math.random() * SIZEOFID);
            idNum.toString();
            id = (STRTOFID + idNum);
        }while(id.length != (ID_DIGITS+1) && notUsed(id));
        console.log(id);
    }

When I call generateID() from my web page, the ID gets logged but false does not get logged(Obviously notUsed function is incomplete). However, if I call each function separately from my web page, both the ID and false get logged. How can I fix or work around this issue? Any comments help.

@Dij the ID getting logged is just a random ID with a single character and 7 digits — Nick Pavini
– Nick Pavini, Commented Aug 17, 2017 at 14:52
@MarcoSalerno when calling generateID() from inside a script tag on a web page? — Nick Pavini
– Nick Pavini, Commented Aug 17, 2017 at 14:53
Apparantly notUsed(id) is not executed. id.length != (ID_DIGITS+1) returns false so second operand is not evaluated — Artem
– Artem, Commented Aug 17, 2017 at 14:53

John Halbert · Accepted Answer · 2017-08-17 14:53:49Z

2

The logical and is short-circuiting because the first comparison is false. The second never gets evaluated, which is why it's not logging. It's not being called.

answered Aug 17, 2017 at 14:53

John Halbert

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6 Comments

Nick Pavini Over a year ago

How can I fix that if it is possible?

Johan Karlsson Over a year ago

@NickPavini You probably want to use || instead of &&

John Halbert Over a year ago

Well if the purpose is to verify that the ID as generated is not used by another user, then just call notUsed only. Your code as written will guarantee the length of idNum to be 8 characters, I don't think you need that check.

Nick Pavini Over a year ago

@JohanKarlsson but I need both circumstances to be true.

Johan Karlsson Over a year ago

@NickPavini !(A && B) == !A || !B

|

Dmitrii · Accepted Answer · 2017-08-17 15:07:38Z

1

It`s happened because first condition in while id.length != (ID_DIGITS+1) return false, if first condition return false next conditions will not be called

Example:

function imreturnTrue() {
  console.log('imreturnTrue');
  return true
};

function impreturnFalse() {
   console.log('impreturnFalse');
   return false
};

function imreturnTrue1() {
    console.log('imreturnTrue1');
    return true
};
let example = imreturnTrue() && impreturnFalse() && imreturnTrue1();
// imreturnTrue impreturnFalse

let example1 = imreturnTrue() && imreturnTrue1() && impreturnFalse() ; 
// imreturnTrue imreturnTrue1 impreturnFalse

let example2 = impreturnFalse() && imreturnTrue() && imreturnTrue1() ; 
// impreturnFalse

edited Aug 17, 2017 at 15:07

answered Aug 17, 2017 at 14:57

Dmitrii

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