• Global community
    • Language:
      • Deutsch
      • English
      • Español
      • Français
      • Português
  • 日本語コミュニティ
    Dedicated community for Japanese speakers
  • 한국 커뮤니티
    Dedicated community for Korean speakers

Function with Multiple Returns

Participant ,
Jan 28, 2020 Jan 28, 2020

Copy link to clipboard

Copied

I have this little script for getting objects on a given page:

function getFieldOn(name, p){//finds (the first) field on page p with 'name' in its name
    var fields;
    for(var i = 0; i < this.numFields; i++){
        var f = this.getField(this.getNthFieldName(i));
        if ((f.name.indexOf(name) > -1) && (f.page == p)) return f;
    }
}

I'd like to modify this so it can return a single object if that's all it finds, and return an array of objects if there are multiple objects sharing the same name or partial name. Can I have two types of return values like that? How can I modify this code?

TOPICS
Acrobat SDK and JavaScript

Views

91

Likes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines

correct answers 1 Correct answer

Community Expert , Jan 28, 2020 Jan 28, 2020

Add an array object to collect all the fields. 

 

    var fieldsd, aRslts = [];
    for(var i = 0; i < this.numFields; i++){
        var f = this.getField(this.getNthFieldName(i));
        if ((f.name.indexOf(name) > -1) && (f.page == p)) aRslt.push(f);
    }
    return (aRslts.length==1)?aRslts[0]:aRslts;

 

Note that this code returns an empty array if there are no fields found.  

Likes

Translate

Translate
Community Expert ,
Jan 28, 2020 Jan 28, 2020

Copy link to clipboard

Copied

You can return a single object or an array of objects.

Likes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Community Expert ,
Jan 28, 2020 Jan 28, 2020

Copy link to clipboard

Copied

Add an array object to collect all the fields. 

 

    var fieldsd, aRslts = [];
    for(var i = 0; i < this.numFields; i++){
        var f = this.getField(this.getNthFieldName(i));
        if ((f.name.indexOf(name) > -1) && (f.page == p)) aRslt.push(f);
    }
    return (aRslts.length==1)?aRslts[0]:aRslts;

 

Note that this code returns an empty array if there are no fields found.  

Thom Parker - Software Developer at PDFScripting
Use the Acrobat JavaScript Reference early and often

Likes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Participant ,
Jan 28, 2020 Jan 28, 2020

Copy link to clipboard

Copied

Sweet, thanks! Why is the logic check needed in the last line of your code?

Likes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Community Expert ,
Jan 28, 2020 Jan 28, 2020

Copy link to clipboard

Copied

The conditional on the return tests for a single result. If there is only one, then it returns just that one. Otherwise the entire array is returned. 

Thom Parker - Software Developer at PDFScripting
Use the Acrobat JavaScript Reference early and often

Likes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Participant ,
Jan 28, 2020 Jan 28, 2020

Copy link to clipboard

Copied

I'm sure this is "best programming practice" at work, but I want to make sure I understand. Why do we need to check for this? What if the last line wre just

return aRslts;

and there was only one value in the array? 

Likes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Community Expert ,
Jan 28, 2020 Jan 28, 2020

Copy link to clipboard

Copied

Then it would only return that one object, not an array.

Personally, I think it's better to know the type of object you're returning, so I would opt for returning an array always, either empty, or with one item, or with multiple items, but it's a matter of preference.

Likes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Community Expert ,
Jan 28, 2020 Jan 28, 2020

Copy link to clipboard

Copied

LATEST

Personally I think you are better off just returning the "aRslts" array as you've just suggested. I presented the code as you asked for it. You specifically asked for two types of return objects. 

Thom Parker - Software Developer at PDFScripting
Use the Acrobat JavaScript Reference early and often

Likes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines