Only include a variable in an if statement, if another variable exists?

Question

The following function is meant to check to see if a custom Date widget (javascript) is empty or not. Problem is, there are many variations of this widget where M/D/Y fields display, or it could be M/D or, M/Y.

Of course, I could hard code all the combinations as if checks, but is there a better way of saying "there are 3 possible nodes, that might have values...if x out of 3 nodes exist AND they all have values, set empty to false."

checkIfEmpty: function () {
    var empty = true;

    var mNode = this.getNode('month');
    var month = mNode ? mNode.value : null;

    var dNode = this.getNode('day');
    var day = dNode ? dNode.value : null;

    var yNode = this.getNode('year');
    var year = yNode ? yNode.value : null;

    if (month && day && year) {
        empty = false;
    }

    return empty;
}

Not sure I understand your question, wouldn't switching the && to an | | solve your issue? — Siva
– Siva, Commented Sep 22, 2015 at 18:06
@Siva well sure - there would be many different variations M+Y, M+D, Y+D, Y+M, D+M, D+Y+M. It would be a rather loaded if statement :) — antonpug
– antonpug, Commented Sep 22, 2015 at 18:09
@hexaheart The concept is that, the date field can consist of as little as 1 field, and as many as 3, in varying combinations. I need to check that for all of the fields that do exist, their .value is not empty. — antonpug
– antonpug, Commented Sep 22, 2015 at 18:14

bingo · Accepted Answer · 2015-09-22 18:13:51Z

1

checkIfEmpty: function () {
    var empty = true;
    var dateParts = [];
    var mNode = this.getNode('month');
    if(mNode && mNode.value){
        dateParts.push('month');
    }

    var dNode = this.getNode('day');
    if(dNode && dNode.value){
        dateParts.push('day');
    }


    var yNode = this.getNode('year');
    if(yNode && yNode.value){
        dateParts.push('year');
    }

    if (dateParts.length) {
        empty = false;
    }

    return empty;
}

answered Sep 22, 2015 at 18:13

bingo

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1 Comment

antonpug Over a year ago

This was along the lines of what I was thinking. So far the most optimal solution I've seen.

epascarello · Accepted Answer · 2015-09-22 18:08:16Z

0

You can add to see if the node does not exist

if ( (!mNode || month) && (!dNode || day) && (!yNode || year) ) {

answered Sep 22, 2015 at 18:08

epascarello

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2 Comments

hexa heart Over a year ago

but if a node is null the associate month / day / year variable will be null. At the end they will return true every time ?

epascarello Over a year ago

If the node does not exist it will return true for that portion of the if check. If the node exists, it checks the month/day/year value.

antonpug · Accepted Answer · 2015-09-22 18:33:49Z

0

checkIfEmpty: function () {
    var empty = false;

    var mNode = this.getNode('month');
    if(mNode && !mNode.value) {
        empty = true;
    }

    var dNode = this.getNode('day');
    if(dNode && !dNode.value) {
        empty = true;
    }

    var yNode = this.getNode('year');
    if(yNode && !yNode.value) {
        empty = true;
    }

    return empty;
}

Trying to solve my own question - so far, this is the most efficient way of achieving what I am trying to do. Anyone, suggestions on how to make it even more efficient?

answered Sep 22, 2015 at 18:33

antonpug

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1 Comment

MinusFour Over a year ago

if mNode or dNode or yNode is empty then empty will be false.

MinusFour · Accepted Answer · 2015-09-22 18:43:25Z

0

If the value property exists for all valid nodes then:

if(mNode && dNode && yNode){
   empty = false;
}

Otherwise:

if(mNode && mNode.value && dNode && dNode.value && yNode && yNode.value){
   empty = false;
}

I am not sure if I followed, but if you need that at least one to be true so empty is false then:

if(mNode || dNode || yNode) {
   empty = false;
}

Again, if the value property is not standard for all nodes:

if((mNode && mNode.value) || (dNode && dNode.value) || (yNode && yNode.value)){
   empty = false;
}

I think it's clearer if you think about it this way:

If (node && node.value) returns a truthy value then the date property exists otherwise the date property doesn't exist.

edited Sep 22, 2015 at 18:43

answered Sep 22, 2015 at 18:26

MinusFour

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