Solidity Web3.js – Convert Solidity Bytes32 to Solidity String in JavaScript

Use web3.js like contractInstance.getItem.call(key).

Or mark getItem as constant: function getItem(address key) constant returns (string) and then you can use:

contractInstance.getItem(key)

web3.js will automatically decode the bytes for you. Contracts only have binary data, hex is a more compact way of viewing that data, and that's why you see hex. The binary data is also encoded according to an ABI, so that values can be distinguished, for example between what's just a number and a string.

This has worked for me so far. Not sure if it's the best way.

function stringToBytes32(string memory source) public pure returns (bytes32 result) {
    bytes memory tempEmptyStringTest = bytes(source);
    if (tempEmptyStringTest.length == 0) {
        return 0x0;
    }

    assembly {
        result := mload(add(source, 32))
    }
}

Also, remember that strings in solidity are UTF8 so after converting them to bytes each byte is not necessarily a character.

EDIT: shorter version, should work the same.