How to use the @polkadot/util/u8a/toU8a function in @polkadot/util

// Copyright 2017-2018 @polkadot/client-db authors & contributors
// This software may be modified and distributed under the terms
// of the ISC license. See the LICENSE file for details.

import toU8a from '@polkadot/util/u8a/toU8a';

import TrieDb from './Trie/Memory';

const EMPTY_ROOT = toU8a('0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421');
const HELLO_ROOT = toU8a('0x0a915659b88f80bfa200570bd2767a6ab8cb0a4e44fd240cc5ed7a27728c4531');
const FOO_ROOT = toU8a('0xed4e32371288ee83be74f78fb492f01261b7c3dc9c422581bb705c4376492dc6');

describe('TrieDb', () => {
  let memory = new TrieDb();

  it('starts with the default root', () => {
    expect(
      memory.getRoot()
    ).toEqual(EMPTY_ROOT);
  });

  it('has the correct root after a single insertion', () => {
    memory.put(toU8a('hello'), toU8a('world'));

    expect(

export default function decode (type: Param$Types, _input: Uint8Array | string | null | undefined, version: EncodingVersions, isStorage: boolean = false): Param$Decoded {
  const input: Uint8Array | null | undefined = isUndefined(_input) || isNull(_input)
    ? _input
    : toU8a(_input);

  if (Array.isArray(type)) {
    // Arrays have single entries, Tuples will have multiple types
    if (type.length === 1) {
      return decodeArray(type, input, version, isStorage);
    } else {
      return decodeTuple(type, input, version, isStorage);
    }
  }

  return decodeValue(decode, type, input, version, isStorage);
}

it('should delete from a branch', (): void => {
      trie.del(toU8a('doge'));

      expect(
        trie.get(toU8a('doge'))
      ).toEqual(null);
      expect(
        trie.getRoot()
      ).toEqual(
        new Uint8Array([
          43, 119, 232, 84, 123, 197, 94, 42, 149, 34, 124, 147, 159, 159, 157, 103, 149, 45, 225, 233, 112, 160, 23, 224, 145, 11, 229, 16, 176, 144, 175, 243
        ])
      );
    });
  });

it('should update a value', (): void => {
      trie.put(toU8a('test'), toU8a('two'));

      expect(
        trie.get(toU8a('test'))
      ).toEqual(toU8a('two'));
      expect(
        trie.getRoot()
      ).toEqual(
        new Uint8Array([
          127, 237, 74, 184, 190, 46, 103, 129, 65, 141, 13, 96, 61, 232, 146, 13, 56, 32, 59, 29, 246, 58, 175, 140, 72, 182, 196, 103, 230, 245, 229, 148
        ])
      );
    });

it('should get a value', (): void => {
      expect(
        trie.get(toU8a('test'))
      ).toEqual(toU8a('one'));
    });

it('encodes KeyValue -> Uint8Array properly', () => {
    expect(
      encode('KeyValue', {
        key: toU8a('0x11'),
        value: toU8a('0x9988')
      })
    ).toEqual(
      new Uint8Array([
        1, 0, 0, 0,
        0x11,
        2, 0, 0, 0,
        0x99, 0x88
      ])
    );
  });
});

it('has the correct root after a second insertion', () => {
    memory.put(toU8a('foo'), toU8a('bar'));

    expect(
      memory.getRoot()
    ).toEqual(
      FOO_ROOT
    );
  });

it('creates a snapshot of the (relevant) trie data', () => {
    const root = new Uint8Array([43, 119, 232, 84, 123, 197, 94, 42, 149, 34, 124, 147, 159, 159, 157, 103, 149, 45, 225, 233, 112, 160, 23, 224, 145, 11, 229, 16, 176, 144, 175, 243]);
    const trie = new Trie();
    const back = new Trie();

    trie.put(toU8a('test'), toU8a('one'));
    trie.put(toU8a('test'), toU8a('two'));
    trie.del(toU8a('test'));
    trie.put(toU8a('test'), toU8a('one'));
    trie.put(toU8a('doge'), toU8a('coin'));
    trie.del(toU8a('doge'));

    trie.snapshot(back, () => {});

    expect(back.getRoot()).toEqual(root);
    expect(trie.get(toU8a('test'))).toEqual(toU8a('one'));
  });

decode(
        nullDecoder,
        'KeyValue',
        new Uint8Array([
          4, 0, 0, 0,
          0x11, 0x22, 0x33, 0x44,
          9, 0, 0, 0,
          0x99, 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11
        ]),
        'poc-1'
      )
    ).toEqual({
      length: (4 + 4 + 4 + 9),
      value: {
        key: toU8a('0x11223344'),
        value: toU8a('0x998877665544332211')
      }
    });
  });