> ## Documentation Index
> Fetch the complete documentation index at: https://algolia.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Filter Numeric Comparison

> Lets users refine search results based on numeric comparison.

export const FlavorSwitcher = ({current, baseHref = "", options = [], label = "InstantSearch framework"}) => {
  if (options.length === 0) {
    return <div className="not-prose" role="alert" style={{
      margin: "0.25rem 0 1.5rem",
      padding: "0.75rem",
      border: "1px solid #f59e0b",
      borderRadius: "0.625rem",
      color: "inherit",
      fontSize: "0.875rem"
    }}>
        FlavorSwitcher requires at least one option.
      </div>;
  }
  const selected = options.find(option => option.value === current) ?? options[0];
  return <div className="not-prose mint-flavor-switcher">
      <style>{`
        .mint-flavor-switcher {
          --mfs-bg: #ffffff;
          --mfs-bg-hover: #f4f4f5;
          --mfs-bg-current: #eef2ff;
          --mfs-border: #d4d4d8;
          --mfs-fg: #18181b;
          --mfs-muted: #71717a;
          --mfs-accent: #4f46e5;
          position: relative;
          width: min(100%, 19rem);
          margin: 0.25rem 0 1.5rem;
          color: var(--mfs-fg);
          font-size: 0.875rem;
          line-height: 1.25rem;
        }

        .dark .mint-flavor-switcher {
          --mfs-bg: #18181b;
          --mfs-bg-hover: #27272a;
          --mfs-bg-current: #272747;
          --mfs-border: #3f3f46;
          --mfs-fg: #fafafa;
          --mfs-muted: #a1a1aa;
          --mfs-accent: #a5b4fc;
        }

        .mint-flavor-switcher details {
          position: relative;
        }

        .mint-flavor-switcher summary {
          display: flex;
          min-height: 2.75rem;
          box-sizing: border-box;
          align-items: center;
          justify-content: space-between;
          gap: 0.75rem;
          padding: 0.625rem 0.75rem;
          border: 1px solid var(--mfs-border);
          border-radius: 0.625rem;
          background: var(--mfs-bg);
          color: var(--mfs-fg);
          cursor: pointer;
          font-weight: 600;
          list-style: none;
          transition: border-color 150ms ease, box-shadow 150ms ease;
        }

        .mint-flavor-switcher summary::-webkit-details-marker {
          display: none;
        }

        .mint-flavor-switcher summary:hover {
          border-color: var(--mfs-accent);
        }

        .mint-flavor-switcher summary:focus-visible {
          outline: 2px solid var(--mfs-accent);
          outline-offset: 2px;
        }

        .mint-flavor-switcher__label {
          overflow: hidden;
          text-overflow: ellipsis;
          white-space: nowrap;
        }

        .mint-flavor-switcher__chevron {
          flex: none;
          transition: transform 150ms ease;
        }

        .mint-flavor-switcher details[open] .mint-flavor-switcher__chevron {
          transform: rotate(180deg);
        }

        .mint-flavor-switcher__menu {
          position: absolute;
          z-index: 50;
          top: calc(100% + 0.375rem);
          left: 0;
          width: 100%;
          box-sizing: border-box;
          margin: 0;
          padding: 0.375rem;
          border: 1px solid var(--mfs-border);
          border-radius: 0.625rem;
          background: var(--mfs-bg);
          box-shadow: 0 12px 30px rgb(0 0 0 / 16%);
          list-style: none;
        }

        .mint-flavor-switcher__menu li {
          margin: 0;
          padding: 0;
        }

        .mint-flavor-switcher__option {
          display: grid;
          gap: 0.125rem;
          padding: 0.625rem 0.75rem;
          border-radius: 0.4rem;
          color: var(--mfs-fg);
          text-decoration: none;
        }

        .mint-flavor-switcher__option:hover {
          background: var(--mfs-bg-hover);
        }

        .mint-flavor-switcher__option:focus-visible {
          outline: 2px solid var(--mfs-accent);
          outline-offset: -2px;
        }

        .mint-flavor-switcher__option[aria-current="page"] {
          background: var(--mfs-bg-current);
          color: var(--mfs-accent);
        }

        .mint-flavor-switcher__name {
          font-weight: 600;
        }

        .mint-flavor-switcher__description {
          color: var(--mfs-muted);
          font-size: 0.8125rem;
        }

        @media (prefers-reduced-motion: reduce) {
          .mint-flavor-switcher summary,
          .mint-flavor-switcher__chevron {
            transition: none;
          }
        }
      `}</style>

      <details>
        <summary aria-label={`${label}: ${selected.label}`}>
          <span className="mint-flavor-switcher__label">{selected.label}</span>
          <svg className="mint-flavor-switcher__chevron" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
            <path d="m6 9 6 6 6-6" />
          </svg>
        </summary>

        <ul className="mint-flavor-switcher__menu" aria-label={label}>
          {options.map(option => {
    const isCurrent = option.value === selected.value;
    const href = option.href ?? `${baseHref.replace(/\/$/, "")}/${encodeURIComponent(option.value)}`;
    return <li key={option.value}>
                <a className="mint-flavor-switcher__option" href={href} aria-current={isCurrent ? "page" : undefined}>
                  <span className="mint-flavor-switcher__name">
                    {option.label}
                  </span>
                  {option.description ? <span className="mint-flavor-switcher__description">
                      {option.description}
                    </span> : null}
                </a>
              </li>;
  })}
        </ul>
      </details>
    </div>;
};

<div className="mint-flavor-switcher-slot not-prose">
  <FlavorSwitcher
    current="ios"
    baseHref="/doc/api-reference/widgets/filter-comparison"
    options={[
{ value: "ios", label: "iOS", description: "InstantSearch iOS" },
{ value: "android", label: "Android", description: "InstantSearch Android" },
]}
  />
</div>

```swift Signature theme={"system"}
FilterComparisonConnector<Number: Comparable & DoubleRepresentable>(
  searcher: HitsSearcher,
  filterState: FilterState,
  attribute: Attribute,
  numericOperator: Filter.Numeric.Operator,
  number: Number?,
  bounds: ClosedRange<Number>?,
  operator: RefinementOperator,
  groupName: String?
)
```

<Card title="Explore example code" icon="github" href="https://github.com/algolia/instantsearch-ios/tree/master/Examples/Showcase">
  Browse the Filter Numeric Comparison example code on GitHub.
</Card>

## About this widget

Filter Numeric Comparison is a view to filter on a numeric value using a comparison operator.

## Examples

Instantiate a `FilterComparisonConnector` and launch an initial search on its searcher.

```swift Swift icon=code theme={"system"}
let searcher = HitsSearcher(appID: "YourApplicationID",
                            apiKey: "YourApiKey",
                            indexName: "YourIndexName")
let filterState = FilterState()

let stepperController = NumericStepperController()

let filterComparisonConnector = FilterComparisonConnector<Double>(searcher: searcher,
                                                                  filterState: filterState,
                                                                  numericOperator: .greaterThanOrEqual,
                                                                  attribute: "price",
                                                                  controller: stepperController)

searcher.search()
```

### Low-level API

If you want to fully control the Filter Numeric Comparison components and connect them manually, use the following components:

* `Searcher`. The [`Searcher`](/doc/api-reference/widgets/instantsearch/ios) that handles your searches.
* `FilterState`. The current state of the filters.
* `NumberInteractor<T>`. The logic applied to the numeric value.
* `NumberController`. The view controller that renders the numeric value.

```swift Swift icon=code theme={"system"}
let searcher = HitsSearcher(appID: "YourApplicationID",
                            apiKey: "YourApiKey",
                            indexName: "YourIndexName")
let filterState = FilterState()
let numberInteractor = NumberInteractor<Double>()
let stepperController = NumericStepperController()

interactor.connectSearcher(searcher, attribute: "price")
interactor.connectFilterState(filterState,
                              attribute: attribute,
                              numericOperator: numericOperator,
                              operator: .greaterThanOrEqual)
interactor.connectNumberController(stepperController)

searcher.search()
```

### SwiftUI

InstantSearch provides the `NumberObservableController` as a state model,
which is an implementation of the `NumberController` interface.
You need to connect `NumberObservableController` to the `FilterComparisonConnector` or `NumberInteractor` like any other `NumberController` implementation.

```swift Swift icon=code theme={"system"}
struct ContentView: View {

  @ObservedObject var priceController: NumberObservableController<Double>

  var body: some View {
    HStack {
      Stepper(value: $priceController.value,
              in: priceController.bounds,
              step: 0.1) {
        HStack {
          Text("Price:")
          Spacer()
          Text(String(format: "%.2f", priceController.value))
        }
      }
    }
  }

}
```

If you prefer to create a custom SwiftUI view that presents the numeric range,
you can directly use the `NumberObservableController` as a data model.
It provides `value` and `bounds` properties to streamline the design process of your custom SwiftUI view.

## Parameters

<ParamField body="searcher" type="HitsSearcher" required>
  The Searcher that handles your searches
</ParamField>

<ParamField body="filterState" type="FilterState" required>
  The [`FilterState`](/doc/api-reference/widgets/filter-state/ios) that holds filters.
</ParamField>

<ParamField body="attribute" type="Attribute" required>
  The attribute to filter on.
</ParamField>

<ParamField body="numericOperator" type="Filter.Numeric.Operator" required>
  The comparison operator to apply.
</ParamField>

<ParamField body="number" type="Number: Comparable & DoubleRepresentable" post={["default: nil"]}>
  The initial numeric value to filter on.
</ParamField>

<ParamField body="bounds" type="ClosedRange<Number>?" post={["default: nil"]}>
  The optional bounds limiting the max and the min value of the number.
</ParamField>

<ParamField body="operator" type="RefinementOperator" post={["default: .and"]} required>
  Whether the filter is added to a conjuncitve(`and`) or  a disjuncitve (`or`) group in the filter state.
</ParamField>

<ParamField body="groupName" type="String?" post={["default: nil"]}>
  Filter group name in the filter state.
  If not specified, the attribute value is used as the group name.
</ParamField>

## Controller

<ParamField body="controller" type="NumberController" required>
  Controller interfacing with a concrete number view.

  ```swift Swift icon=code theme={"system"}
  let controller = MyNumberController() // your `NumberController` implementation
  filterComparisonConnector.connectNumberController(controller)
  ```
</ParamField>