# Utilities
## Hat & Tree ID Utils
Following are utility functions to handle various hat & tree ID formats. More information about hat IDs can be found [here](https://docs.hatsprotocol.xyz/for-developers/hats-protocol-for-developers/hat-ids).
### hatIdDecimalToHex
Convert a hat ID from decimal to hex.
```typescript
import { hatIdDecimalToHex } from "@hatsprotocol/sdk-v1-core";
const hatIdHex = hatIdDecimalToHex(hatId);
```
***Arguments***:
```typescript
hatId: bigint
```
`hatId` - Hat ID in decimal format.
***Response***:
```typescript
`0x${string}`
```
Hat ID in a hex format.
### hatIdHexToDecimal
Convert a hat ID from hex to decimal.
```typescript
import { hatIdHexToDecimal } from "@hatsprotocol/sdk-v1-core";
const hatIdDecimal = hatIdHexToDecimal(hatId);
```
***Arguments***:
```typescript
hatId: string
```
`hatId` - Hat ID in hex format.
***Response***:
```typescript
bigint
```
Hat ID in a decimal format.
### treeIdDecimalToHex
Convert a tree ID from decimal to hex. A tree ID is the first 4 bytes in a hat ID.
```typescript
import { treeIdDecimalToHex } from "@hatsprotocol/sdk-v1-core";
const treeIdHex = treeIdDecimalToHex(treeId);
```
***Arguments***:
```typescript
treeId: number
```
`treeId` - Tree ID in decimal format.
***Response***:
```typescript
`0x${string}`
```
Tree ID in a hex format.
### treeIdHexToDecimal
Convert a tree ID from hex to decimal. A tree ID is the first 4 bytes in a hat ID.
```typescript
import { treeIdHexToDecimal } from "@hatsprotocol/sdk-v1-core";
const treeIdDecimal = treeIdHexToDecimal(treeId);
```
***Arguments***:
```typescript
treeId: string
```
`treeId` - Tree ID in hex format.
***Response***:
```typescript
number
```
Tree ID in a decimal format.
### treeIdToTopHatId
Convert a tree ID to its top-hat ID. A tree ID is the first 4 bytes in a hat ID.
```typescript
import { treeIdToTopHatId } from "@hatsprotocol/sdk-v1-core";
const tophatId = treeIdToTopHatId(treeId);
```
***Arguments***:
```typescript
treeId: number
```
`treeId` - Tree ID in decimal format.
***Response***:
```typescript
bigint
```
Top-hat ID in decimal format.
### hatIdToTreeId
Convert a hat ID to its tree ID. A tree ID is the first 4 bytes in a hat ID.
```typescript
import { hatIdToTreeId } from "@hatsprotocol/sdk-v1-core";
const treeId = hatIdToTreeId(hatId);
```
***Arguments***:
```typescript
hatId: bigint
```
`hatId` - Hat ID in decimal format.
***Response***:
```typescript
number
```
Tree ID of the hat, in a decimal format.
### hatIdDecimalToIp
The IP format may be used as a "pretty" hat ID format for presenting.
For example, a hat with a hex ID of:\
`0x00000001000a0002000000000000000000000000000000000000000000000000` will have an IP format of 1.10.2 - Each level is separated by a dot and presented as a decimal number, excluding zeros.
```typescript
import { hatIdDecimalToIp } from "@hatsprotocol/sdk-v1-core";
const hatIdIp = hatIdDecimalToIp(hatId);
```
***Arguments***:
```typescript
hatId: bigint
```
`hatId` - Hat ID in decimal format.
***Response***:
```typescript
string
```
Hat ID in IP format.
### hatIdIpToDecimal
Convert a hat ID from an IP format, to a decimal format.
import { hatIdIpToDecimal } from "@hatsprotocol/sdk-v1-core";
const hatIdDecimal = hatIdIpToDecimal(hatId);
***Arguments***:
```typescript
hatId: string
```
`hatId` - Hat ID in IP format.
***Response***:
```typescript
bigint
```
Hat ID in decimal format.
## Constants
Following are Hats-specific exported constant values.
import {
HATS_V1, // Hats-Protocol v1 contract address
MAX_LEVELS, // Max levels on a Hats tree
MAX_LEVEL_HATS, // Max amount of hats on each level (excluding level 0)
ZERO_ID, // The zero Hat ID in hex format
FALLBACK_ADDRESS, // The fallback address for eligibility and toggle
} from "@hatsprotocol/sdk-v1-core";