Saving a variable's value using Knockout loop within an HTML document

Question

Saving a variable's value using Knockout loop within an HTML document

As a newcomer to KO, I have been utilizing the following code in my HTML file to print a specific value:

<!-- ko foreach: { data: JSON.parse($parent.options), as: 'option' } -->
    <!-- ko if: option.label === 'AAA' || option.label === 'BBB'  -->
        <dd class="values" data-bind="html: option.value"></dd>
    <!-- /ko -->    
<!-- /ko -->

This setup is functioning properly. However, I have a new requirement where I need to store all the values from the loop into a variable and output them after the loop just like we would do in PHP:

foreach($data as $key=> $index){
    if($key==0)
        $var = $index['value'];
    else
        $var .= ' '.$index['value'];    
}

echo $var

I am looking for a way to achieve the same result within KO's HTML file using the above mentioned KO loop structure.

javascript knockout.js

Answer 1

Answer №1

To enhance functionality, consider creating 2 specializedcomputed properties as follows:

parsedOptions: extracts the parsed JSON data.
concatenatedValues: combines values into a string with space separation using map and join.

Next, iterate through the parsedOptions within a foreach loop. Then bind the concatenatedValues to a span.

const JSONstring = JSON.stringify([{ label: "AAA", value: 1 },{ label: "BBB", value: 2 },{ label: "CCC", value: 3 }]);

const viewModel = function() {  
  this.options = JSONstring;
  
  this.parsedOptions = ko.computed(() => {
    return JSON.parse(this.options)
  });
  
  this.concatenatedValues = ko.computed(() => {
    return this.parsedOptions().map(a => a.value).join(' ')
  });
}

ko.applyBindings(new viewModel())

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>

<!-- ko foreach: { data: parsedOptions, as: 'option' } -->
    <!-- ko if: option.label === 'AAA' || option.label === 'BBB'  -->
        <dd class="values" data-bind="html: option.value"></dd>
    <!-- /ko -->
<!-- /ko -->

<br> All values:
<span data-bind="text: concatenatedValues"></span>

Answer 2

To enhance functionality, consider creating 2 specializedcomputed properties as follows:

parsedOptions: extracts the parsed JSON data.
concatenatedValues: combines values into a string with space separation using map and join.

Next, iterate through the parsedOptions within a foreach loop. Then bind the concatenatedValues to a span.

const JSONstring = JSON.stringify([{ label: "AAA", value: 1 },{ label: "BBB", value: 2 },{ label: "CCC", value: 3 }]);

const viewModel = function() {  
  this.options = JSONstring;
  
  this.parsedOptions = ko.computed(() => {
    return JSON.parse(this.options)
  });
  
  this.concatenatedValues = ko.computed(() => {
    return this.parsedOptions().map(a => a.value).join(' ')
  });
}

ko.applyBindings(new viewModel())

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>

<!-- ko foreach: { data: parsedOptions, as: 'option' } -->
    <!-- ko if: option.label === 'AAA' || option.label === 'BBB'  -->
        <dd class="values" data-bind="html: option.value"></dd>
    <!-- /ko -->
<!-- /ko -->

<br> All values:
<span data-bind="text: concatenatedValues"></span>

Saving a variable's value using Knockout loop within an HTML document

Answer №1

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