Example: Buy ram

const result = await api.transact({
  actions: [{
    account: 'eosio',
    name: 'buyrambytes',
    authorization: [{
      actor: 'useraaaaaaaa',
      permission: 'active',
    }],
    data: {
      payer: 'useraaaaaaaa',
      receiver: 'useraaaaaaaa',
      bytes: 8192,
    },
  }]
}, {
  blocksBehind: 3,
  expireSeconds: 30,
});

Example: Stake

const result = await api.transact({
  actions: [{
    account: 'eosio',
    name: 'delegatebw',
    authorization: [{
      actor: 'useraaaaaaaa',
      permission: 'active',
    }],
    data: {
      from: 'useraaaaaaaa',
      receiver: 'useraaaaaaaa',
      stake_net_quantity: '1.0000 SYS',
      stake_cpu_quantity: '1.0000 SYS',
      transfer: false,
    }
  }]
}, {
  blocksBehind: 3,
  expireSeconds: 30,
});

Example: Unstake

const result = await api.transact({
  actions: [{
    account: 'eosio',
    name: 'undelegatebw',
    authorization: [{
      actor: 'useraaaaaaaa',
      permission: 'active',
    }],
    data: {
      from: 'useraaaaaaaa',
      receiver: 'useraaaaaaaa',
      unstake_net_quantity: '1.0000 SYS',
      unstake_cpu_quantity: '1.0000 SYS',
      transfer: false,
    }
  }]
}, {
  blocksBehind: 3,
  expireSeconds: 30,
});

Example: Create New Account (multiple actions)

const result = await api.transact({
  actions: [{
    account: 'eosio',
    name: 'newaccount',
    authorization: [{
      actor: 'useraaaaaaaa',
      permission: 'active',
    }],
    data: {
      creator: 'useraaaaaaaa',
      name: 'mynewaccount',
      owner: {
        threshold: 1,
        keys: [{
          key: 'PUB_R1_6FPFZqw5ahYrR9jD96yDbbDNTdKtNqRbze6oTDLntrsANgQKZu',
          weight: 1
        }],
        accounts: [],
        waits: []
      },
      active: {
        threshold: 1,
        keys: [{
          key: 'PUB_R1_6FPFZqw5ahYrR9jD96yDbbDNTdKtNqRbze6oTDLntrsANgQKZu',
          weight: 1
        }],
        accounts: [],
        waits: []
      },
    },
  },
  {
    account: 'eosio',
    name: 'buyrambytes',
    authorization: [{
      actor: 'useraaaaaaaa',
      permission: 'active',
    }],
    data: {
      payer: 'useraaaaaaaa',
      receiver: 'mynewaccount',
      bytes: 8192,
    },
  },
  {
    account: 'eosio',
    name: 'delegatebw',
    authorization: [{
      actor: 'useraaaaaaaa',
      permission: 'active',
    }],
    data: {
      from: 'useraaaaaaaa',
      receiver: 'mynewaccount',
      stake_net_quantity: '1.0000 SYS',
      stake_cpu_quantity: '1.0000 SYS',
      transfer: false,
    }
  }]
}, {
  blocksBehind: 3,
  expireSeconds: 30,
});