Replace the value of Undefined with an empty string

Question

Replace the value of Undefined with an empty string

I have been utilizing exif.js to extract metadata from the images I upload on a content management system (CMS). However, sometimes when an image does not contain any metadata, certain values may show up as "undefined". My goal is to replace these "undefined" values with empty strings. Stanley's approach seems like a viable solution:

var i;
var j = (typeof(i) !== 'undefined' ? i : '');
console.log(j); // ''

Despite spending hours analyzing the code, I am unable to pinpoint how exif.js generates the undefined value that I need to change to an empty string.

You can access the exif.js library here: https://github.com/exif-js/exif-js/blob/master/exif.js

javascript exif-js

Answer 1

Answer №1

let variable = "undefined";

You have assigned a string to variable, so this cannot test if it is undefined.

To check the type of a variable and verify that it is not 'undefined', you can use

typeof (variable) !== 'undefined'

. You can then utilize Short Circuit Operators to return the value.

For example:

// When variable is not set
// variable === undefined

let result = (typeof (variable) !== 'undefined' ? variable : 'not found');

console.log(result); // 'not found'

Visit jsfiddle for demonstration

Answer 2

let variable = "undefined";

You have assigned a string to variable, so this cannot test if it is undefined.

To check the type of a variable and verify that it is not 'undefined', you can use

typeof (variable) !== 'undefined'

. You can then utilize Short Circuit Operators to return the value.

For example:

// When variable is not set
// variable === undefined

let result = (typeof (variable) !== 'undefined' ? variable : 'not found');

console.log(result); // 'not found'

Visit jsfiddle for demonstration

Answer 3

Answer №2

After encountering a similar issue, I found a solution that worked well for me:

To prevent undefined variables from causing issues in the EXIF.JS library, you can utilize `if` statements within the `.getData` function. This code snippet is typically implemented within your page's script when following examples from the EXIF.JS Github repository.

  EXIF.getData(img, function() {
                var model = EXIF.getTag(this, "Model");
                
                if (model) {
                  var modelDataSpan = document.getElementById('model-'+id);
                  modelDataSpan.innerHTML = `${model}`;
                }

Answer 4

After encountering a similar issue, I found a solution that worked well for me:

To prevent undefined variables from causing issues in the EXIF.JS library, you can utilize `if` statements within the `.getData` function. This code snippet is typically implemented within your page's script when following examples from the EXIF.JS Github repository.

  EXIF.getData(img, function() {
                var model = EXIF.getTag(this, "Model");
                
                if (model) {
                  var modelDataSpan = document.getElementById('model-'+id);
                  modelDataSpan.innerHTML = `${model}`;
                }

Replace the value of Undefined with an empty string

Answer №1

Answer №2

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