JSON

Overview

The IJson.sol precompile enables EVM smart contracts to manipulate JSON data.

In this article, you'll find a full list of available methods, allowing you to handle different value types:

All value types
Basic types and numbers
Arrays and nested objects

To learn how to use this precompile, refer to the following guides:

Code

You can find the JSON precompile code on GitHub: IJson.sol

Precompile address

To reference the IJson precompile in your code, use the following precompile address:

0x0000000000000000000000000000000000000904

All value types

Create a new root object

Method: newJson()
Description: Creates an empty root JSON object.

Code:

function newJson() external view returns (bytes memory);

Output:
```
@return The created JSON as bytes.
```
Usage example: Create a new root object

Get a value

Method: get()
Description: Returns a value by key.

Code:

function get(
    bytes memory input,
    string memory key
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The value as bytes.
```
Usage example: Get a value

Remove a pair

Method: remove()
Description: Removes a key-value pair from the root object.

Code:

function remove(
    bytes memory input,
    string memory key
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to remove.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Remove a pair

Get multiple values

Method: read()
Description: Returns multiple values by their keys. Requires passing an array of keys: see the ReadKeyValue struct.

Code:

function read(
    bytes memory input,
    ReadKeyValue[] memory keyValues
) external view returns (bytes[] memory);

Parameters:

@param input The JSON input as bytes.
@param keyValues The key-value pairs to read.

Output:

@return The array of key-value pairs as bytes.

Usage example: Get multiple pairs

Set multiple pairs

Method: write()
Description: Sets multiple key-value pairs. Requires passing an array of pairs: seee the SetKeyValue struct.

Code:

function write(
    bytes memory input,
    SetKeyValue[] memory keyValues
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param keyValues The key-value pairs to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set multiple pairs

Basic types and numbers

Get a string value

Method: getString()
Description: Returns a string value by key.

Code:

function getString(
    bytes memory input,
    string memory key
) external view returns (string memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The string value.
```
Usage example: Get a string value

Get a boolean value

Method: getBool()
Description: Returns a boolean value by key.

Code:

function getBool(
    bytes memory input,
    string memory key
) external view returns (bool);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The boolean value.
```
Usage example: Get a boolean value

Get an address value

Method: getAddress()
Description: Returns an address value by key.

Code:

function getAddress(
    bytes memory input,
    string memory key
) external view returns (address);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The address value.
```
Usage example: Get an address value

Get a uint256 value

Method: getUint256()
Description: Returns a uint256 value by key.

Code:

function getUint256(
    bytes memory input,
    string memory key
) external view returns (uint256);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The uint256 value
```
Usage example: Get a uint256 value

Get an int256 value

Method: getInt256()
Description: Returns an int256 value by key.

Code:

function getInt256(
    bytes memory input,
    string memory key
) external view returns (int256);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The int256 value.
```
Usage example: Get an int256 value

Get a float value

Method: getFloat()
Description: Returns a float value by key.

Code:

function getFloat(
    bytes memory input,
    string memory key,
    int64 decimals
) external view returns (int256);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.
@param decimals The number of decimal places.

Output:
```
@return The float value as int256.
```
Usage example: Get a float value

Set a string pair

Method: setString()
Description: Sets a string key-value pair.

Code:

function setString(
    bytes memory input,
    string memory key,
    string memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The string value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a string pair

Set a boolean pair

Method: setBool()
Description: Sets a boolean key-value pair.

Code:

function setBool(
    bytes memory input,
    string memory key,
    bool value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The boolean value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a boolean pair

Set an address pair

Method: setAddress()
Description: Sets an address key-value pair.

Code:

function setAddress(
    bytes memory input,
    string memory key,
    address value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The address value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set an address pair

Set a bytes pair

Method: setBytes()
Description: Set a bytes key-value pair.

Code:

function setBytes(
    bytes memory input,
    string memory key,
    bytes memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The bytes value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a bytes pair

Set a uint256 pair

Method: setUint256()
Description: Set a uint256 key-value pair.

Code:

function setUint256(
    bytes memory input,
    string memory key,
    uint256 value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The uint256 value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a uint256 pair

Set an int256 pair

Method: setInt256()
Description: Set an int256 key-value pair.

Code:

function setInt256(
    bytes memory input,
    string memory key,
    int256 value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The int256 value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set an int256 pair

Set a float pair

Method: setFloat()
Description: Set a float key-value pair.

Code:

function setFloat(
    bytes memory input,
    string memory key,
    int256 value,
    int64 decimals
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The int256 value to set.
@param decimals The number of decimal places.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a float pair

Arrays and nested objects

Get a string array

Method: getStringArray()
Description: Returns a string array value by key.

Code:

function getStringArray(
    bytes memory input,
    string memory key
) external view returns (string[] memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The string array value.
```
Usage example: Get a string array

Get a boolean array

Method: getBoolArray()
Description: Returns a boolean array value by key.

Code:

function getBoolArray(
    bytes memory input,
    string memory key
) external view returns (bool[] memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The boolean array value.
```
Usage example: Get a boolean array

Get an address array

Method: getAddressArray()
Description: Returns an address array value by key.

Code:

function getAddressArray(
    bytes memory input,
    string memory key
) external view returns (address[] memory);

Parameters:

 @param input The JSON input as bytes.
 @param key The key to look up.

Output:
```
@return The address array value.
```
Usage example: Get an address array

Get a uint256 array

Method: getUintArray()
Description: Returns a uint256 array value by key.

Code:

function getUintArray(
    bytes memory input,
    string memory key
) external view returns (uint256[] memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The uint256 array value.
```
Usage example: Get a uint256 array

Get an int256 array

Method: getIntArray()
Description: Returns an int256 array value by key.

Code:

function getIntArray(
    bytes memory input,
    string memory key
) external view returns (int256[] memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The int256 array value.
```
Usage example: Get an int256 array

Get a float array

Method: getFloatArray()
Description: Returns a float array value by key.

Code:

function getFloatArray(
    bytes memory input,
    string memory key,
    int64 decimals
) external view returns (int256[] memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:
```
@return The float array value.
```
Usage example: Get a float array

Get an object array

Method: getObjectsArray()
Description: Returns an object array value by key.

Code:

function getObjectsArray(
    bytes memory input,
    string memory key
) external view returns (bytes[] memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:

@return The nested object value as bytes.

Usage example: Get an object array

Get a nested object

Method: getObject()
Description: Returns a nest object value by key.

Code:

function getObject(
    bytes memory input,
    string memory key
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to look up.

Output:

@return The nested object value as bytes.

Usage example: Get a nested object

Set a string array pair

Method: setStringArray()
Description: Set a string array key-value pair.

Code:

function setStringArray(
    bytes memory input,
    string memory key,
    string[] memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The string array value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a string array pair

Set an address array pair

Method: setAddressArray()
Description: Set an address array key-value pair.

Code:

function setAddressArray(
    bytes memory input,
    string memory key,
    address[] memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The address array value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set an address array pair

Set a boolean array pair

Method: setBoolArray()
Description: Set a boolean array key-value pair.

Code:

function setBoolArray(
    bytes memory input,
    string memory key,
    bool[] memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The boolean array value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a boolean array pair

Set a uint256 array pair

Method: setUintArray()
Description: Set a uint256 array key-value pair.

Code:

function setUintArray(
    bytes memory input,
    string memory key,
    uint256[] memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The uint256 array value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a uint256 array pair

Set an int256 array pair

Method: setIntArray()
Description: Set an int256 array key-value pair.

Code:

function setIntArray(
    bytes memory input,
    string memory key,
    int256[] memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The int256 array value to set.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set an int256 array pair

Set a float array pair

Method: setFloatArray()
Description: Set a float array key-value pair.

Code:

function setFloatArray(
    bytes memory input,
    string memory key,
    int256[] memory value,
    int64 decimals
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The int256 array value to set.
@param decimals The number of decimal places.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a float array pair

Set an object array pair

Method: setObjectsArray()
Description: Set an object array key-value pair.

Code:

function setObjectsArray(
    bytes memory input,
    string memory key,
    bytes[] memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The nested objects values as bytes.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set an object array pair

Set a nested object pair

Method: setObject()
Description: Set a nested object key-value pair.

Code:

function setObject(
    bytes memory input,
    string memory key,
    bytes memory value
) external view returns (bytes memory);

Parameters:

@param input The JSON input as bytes.
@param key The key to set.
@param value The nested object value as bytes.

Output:
```
@return The modified JSON as bytes.
```
Usage example: Set a nested object pair

Structs

`SetKeyValue`

Description: A struct representing a key and its value type. It's used for getting multiple values.

struct ReadKeyValue {
    string key;
    string valueType;
    int64 decimals;
}

`ReadKeyValue`

Description: A struct representing a key-value pair. It's used for setting multiple pairs.

struct SetKeyValue {
    string key;
    string valueType;
    bytes value;
    int64 decimals;
}

Overview​

Precompile address​

All value types​

Create a new root object​

Get a value​

Remove a pair​

Get multiple values​

Set multiple pairs​

Basic types and numbers​

Get a string value​

Get a boolean value​

Get an address value​

Get a uint256 value​

Get an int256 value​

Get a float value​

Set a string pair​

Set a boolean pair​

Set an address pair​

Set a bytes pair​

Set a uint256 pair​

Set an int256 pair​

Set a float pair​

Arrays and nested objects​

Get a string array​

Get a boolean array​

Get an address array​

Get a uint256 array​

Get an int256 array​

Get a float array​

Get an object array​

Get a nested object​

Set a string array pair​

Set an address array pair​

Set a boolean array pair​

Set a uint256 array pair​

Set an int256 array pair​

Set a float array pair​

Set an object array pair​

Set a nested object pair​

Structs​

SetKeyValue​

ReadKeyValue​

Overview

Precompile address

All value types

Create a new root object

Get a value

Remove a pair

Get multiple values

Set multiple pairs

Basic types and numbers

Get a string value

Get a boolean value

Get an address value

Get a uint256 value

Get an int256 value

Get a float value

Set a string pair

Set a boolean pair

Set an address pair

Set a bytes pair

Set a uint256 pair

Set an int256 pair

Set a float pair

Arrays and nested objects

Get a string array

Get a boolean array

Get an address array

Get a uint256 array

Get an int256 array

Get a float array

Get an object array

Get a nested object

Set a string array pair

Set an address array pair

Set a boolean array pair

Set a uint256 array pair

Set an int256 array pair

Set a float array pair

Set an object array pair

Set a nested object pair

Structs

`SetKeyValue`

`ReadKeyValue`