---
title: types.isType() function
description: types.isType() tests if a value is a specified type.
url: https://docs.influxdata.com/flux/v0/stdlib/types/istype/
estimated_tokens: 3774
product: Flux
version: v0
---

# types.isType() function

-   Flux 0.141.0+
-   View InfluxDB support

`types.isType()` tests if a value is a specified type.

##### Function type signature

```js
(type: string, v: A) => bool where A: Basic
```

For more information, see [Function type signatures](/flux/v0/function-type-signatures/).

## Parameters

### v

(Required) Value to test.

### type

(Required) String describing the type to check against.

**Supported types**:

-   string
-   bytes
-   int
-   uint
-   float
-   bool
-   time
-   duration
-   regexp

## Examples

-   [Filter by value type](#filter-by-value-type)
-   [Aggregate or select data based on type](#aggregate-or-select-data-based-on-type)

### Filter by value type

```js
import "types"

data
    |> filter(fn: (r) => types.isType(v: r._value, type: "string"))
```

[](#view-example-input-and-output)

View example input and output

#### Input data

| _time | *_field | _value |
| --- | --- | --- |
| 2022-01-01T00:00:00Z | foo | 12 |
| 2022-01-01T00:01:00Z | foo | 15 |
| 2022-01-01T00:02:00Z | foo | 9 |

| _time | *_field | _value |
| --- | --- | --- |

| _time | *_field | _value |
| --- | --- | --- |
| 2022-01-01T00:00:00Z | bar | 0jCcsMYM |
| 2022-01-01T00:01:00Z | bar | jHvuDw35 |
| 2022-01-01T00:02:00Z | bar | HE5uCIC2 |

#### Output data

| _time | *_field | _value |
| --- | --- | --- |
| 2022-01-01T00:00:00Z | bar | 0jCcsMYM |
| 2022-01-01T00:01:00Z | bar | jHvuDw35 |
| 2022-01-01T00:02:00Z | bar | HE5uCIC2 |

### Aggregate or select data based on type

```js
import "types"

nonNumericData =
    data
        |> filter(
            fn: (r) =>
                types.isType(v: r._value, type: "string") or types.isType(
                        v: r._value,
                        type: "bool",
                    ),
        )
        |> aggregateWindow(every: 30s, fn: last)

numericData =
    data
        |> filter(
            fn: (r) =>
                types.isType(v: r._value, type: "int") or types.isType(v: r._value, type: "float"),
        )
        |> aggregateWindow(every: 30s, fn: mean)

union(tables: [nonNumericData, numericData])
```

[](#view-example-input-and-output)

View example input and output

#### Input data

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | bool | true |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | bool | true |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | bool | false |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | bool | true |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | bool | false |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | bool | false |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | float | -2.18 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | float | 10.92 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | float | 7.35 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | float | 17.53 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | float | 15.23 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | float | 4.43 |

| *_start | *_stop | _time | _value | *type |
| --- | --- | --- | --- | --- |

| *_start | *_stop | _time | _value | *type |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | -2 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 10 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | 7 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 17 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 15 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | int |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | string | smpl_g9qczs |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | string | smpl_0mgv9n |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | string | smpl_phw664 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | string | smpl_guvzy4 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | string | smpl_5v3cce |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | string | smpl_s9fmgy |

#### Output data

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | bool | false |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:01:00Z | bool | false |

| _time | *_start | *_stop | *type | _value |
| --- | --- | --- | --- | --- |

| _time | *_start | *_stop | *type | _value |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:30Z | 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | float | 5.363333333333333 |
| 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | float | 12.396666666666668 |

| _time | *_start | *_stop | *type | _value |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:30Z | 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | int | 5 |
| 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | int | 12 |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | string | smpl_phw664 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:01:00Z | string | smpl_s9fmgy |

[types](/flux/v0/tags/types/) [tests](/flux/v0/tags/tests/)