EQ Filter Get All Results

[Ashleigh L]

I've got a page that displays courses, which can have tags. For example, my "Javascript" course may have the tag "web". I want to filter the datasource based on the course tags, but if no tag value is passed through (ie. blank string), I want it to ignore the filter.

Right now what's happening is that passing through a "eq" filter w/ an empty string is pulling back only courses that don't have tags - which does make sense. But if I don't pass through a specific tag, I need to get all courses, tagged or not. I also can't switch from "eq", since it has to be a full match, if a tag is passed in. 

Appreciate any help here.

[Daniel]

Hello,

How are you filtering the dataSource? If you are using the filter method then you could check if the value is empty string and clear the filter.

Regards,
Daniel
Telerik

 

 

[Ashleigh L]

I've got it set up on the datasource config right now:

filter: {
    field: "Tag",
    operator: "eq",
    value: filter_field
}

[Daniel]

Hi,

You can also use a condition in this case:

filter: filter_field ? {
    field: "Tag",
    operator: "eq",
    value: filter_field
} : []

Regards,
Daniel
Telerik

 

 

[Ashleigh L]

Perfect, thanks Daniel!

[Ashleigh L]

Is it possible to do the same check w/ multiple filters? I've tried this:

filter: {
    logic: "and",
    filters: [
        filter_val ? {
            field: "Tag",
            operator: "eq",
            value: filter_val
        } : [],
        search ? {
            field: "Name",
            operator: "contains",
            value: search
        } : []
    ]
}

Where "search" is the value of a search field (ie. looking for matches in a huge list based on an item's name), but it always returns zero results (the function populating the datasource does return data, so I know it's the filter).

[Daniel]

Hi,

You should check the values before adding them to the array:

var filter = {
    logic: "and",
    filters: []
};
if (filter_val) {
    filter.filters.push({
        field: "Tag",
        operator: "eq",
        value: filter_val
    });
}
if (search) {
    filter.filters.push({
        field: "Name",
        operator: "contains",
        value: search
    });
}

The filters array should contain only valid filters.

Regards,
Daniel
Telerik

 

 

[Ashleigh L]

Which is what I had asked for originally, but you suggested the condition instead. If this is the more "correct" way to do it, I'll switch. Thank you.

[Ashleigh L]

Wait, how does this get applied to the datasource?

[Daniel]

Hello,

I am not sure if I understand the question but a condition is used in both cases:

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/if...else
• https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Conditional_Operator

You can apply the filter by setting the result to the dataSource:

var filter = {
    logic: "and",
    filters: []
};
if (filter_val) {
    filter.filters.push({
        field: "Tag",
        operator: "eq",
        value: filter_val
    });
}
if (search) {
    filter.filters.push({
        field: "Name",
        operator: "contains",
        value: search
    });
}

var dataSource = new kendo.DataSource({
    filter: filter,
    ...
})

Regards,
Daniel
Telerik