Remote fetching
Fetching capabilities are defined by fetch
property - URL of desired endpoint. Svelecte automatically
resolves “fetch mode” by [query]
placeholder in fetch
property.
When this placeholder [query]
is present, svelecte operates in “query” mode. Otherwise switches to “init” mode,
where remote endpoint is requested, when component is mounted.
<!-- remote fetch is triggered when user types -->
<Svelecte fetch="https://example.com/url?search=[query]">
<!-- remote fetch is triggered on mount -->
<Svelecte fetch="https://example.com/url">
<!-- remote fetch is triggered when user types -->
<Svelecte fetch="https://example.com/url?search=[query]">
<!-- remote fetch is triggered on mount -->
<Svelecte fetch="https://example.com/url">
Fetching default value
Since v4.0 fetching initial value happens automatically on mount, regardless of “fetch mode”. In v3 it was possible only
in init
mode.
<script>
let value="my-value";
let multiValue=['one','two','three'];
</script>
<!-- URL requested: https://example.com/url?search=init&init=my-value -->
<Svelecte fetch="https://example.com/url?search=[query]" bind:value>
<!-- URL requested: https://example.com/url?init=my-value -->
<Svelecte fetch="https://example.com/url" bind:value>
<!-- Multiselect -->
<!-- URL requested: https://example.com/url?search=init&init=one,two,three -->
<Svelecte multiple fetch="https://example.com/url?search[query]" bind:value={multiValue} />
<script>
let value="my-value";
let multiValue=['one','two','three'];
</script>
<!-- URL requested: https://example.com/url?search=init&init=my-value -->
<Svelecte fetch="https://example.com/url?search=[query]" bind:value>
<!-- URL requested: https://example.com/url?init=my-value -->
<Svelecte fetch="https://example.com/url" bind:value>
<!-- Multiselect -->
<!-- URL requested: https://example.com/url?search=init&init=one,two,three -->
<Svelecte multiple fetch="https://example.com/url?search[query]" bind:value={multiValue} />
Manually re-fetching value in “query” mode
Imagine scenario, you have component in query mode with default value set. And you need to change default value, but still keep the same fech mode.
By default changing value='blue'
to value='red'
wouldn’t change the value. You need to call refetchWith(newValue)
API method.
<script>
let value = ['blue'];
let el;
function onClick() {
el.refetchWith('red');
}
</script>
<Svelecte bind:this={el} fetch="https://example.com/url?search=[query]" bind:value />
<button on:click={onClick}>Change selected value to red</button>
<script>
let value = ['blue'];
let el;
function onClick() {
el.refetchWith('red');
}
</script>
<Svelecte bind:this={el} fetch="https://example.com/url?search=[query]" bind:value />
<button on:click={onClick}>Change selected value to red</button>
Results to:
⚠️ Caution with objects
When using objects as value
(with valueAsObject
property set), you always need to set strictMode
to false
.
Otherwise initial value won’t be set. Also using refetchWith
method has no meaning, because you can set object value
directly, no need for fetch request.
Other useful fetch-related properties are:
fetchCallback: Function
Response transform function. It contains JSON-ized response. If not specified, one of following properties are tried in given order:data
,items
,options
or response JSON itself as a fallback. Svelecte expects array to be returned.fetchResetOnBlur: boolean
Setting tofalse
will keep fetched results in dropdown.minQuery: number
Force minimal length of input text to trigger remote request.- Settings
skipSort: true
onsearchProps
to avoid re-ordering search results. More about search settings at Searching page.
User-provided fetch function
In v4.0 whole fetch-related functionality has been reworked and it’s no longer possible to provide your own
fetch function. Properties fetch
and fetchProps
should be enough for every use case.