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

# SISMEMBER

> Check if a member exists in a set

Returns if member is a member of the set stored at key.

## Usage

```typescript theme={null}
await redis.sismember(key, member);
```

## Parameters

<ParamField body="key" type="string" required>
  The key of the set
</ParamField>

<ParamField body="member" type="TData" required>
  The member to check for existence in the set
</ParamField>

## Response

<ResponseField name="result" type="0 | 1">
  Returns `1` if the member exists in the set, `0` otherwise
</ResponseField>

## Examples

### Check if member exists

```typescript theme={null}
await redis.sadd("myset", "hello", "world");
const exists = await redis.sismember("myset", "hello");
console.log(exists); // 1
```

### Check for non-existing member

```typescript theme={null}
await redis.sadd("myset", "hello", "world");
const exists = await redis.sismember("myset", "foo");
console.log(exists); // 0
```

### Using in conditionals

```typescript theme={null}
const isMember = await redis.sismember("users:premium", "user:123");
if (isMember === 1) {
  console.log("User has premium access");
} else {
  console.log("User does not have premium access");
}
```

### Check membership with custom types

```typescript theme={null}
await redis.sadd("numbers", 1, 2, 3, 4, 5);
const exists = await redis.sismember("numbers", 3);
console.log(exists); // 1
```