hsetnx

1. 基本語法

hsetnx(hkey, subkey , value, callback)

如果hkey或subkey不存在，才會新增資料，並回傳1；否則，不進行任何動作，回傳0。

TypeScript

const dict = {
    name: 'Ellie Fredricksen', 
    gender: 'F', 
    age: '78',
    hobby: 'adventure'
};

client.hmset('user:7', dict);
client.hgetall('user:7', (err, obj) => {
    console.log(obj);
    console.log('---------------');
});


client.hsetnx('user:7', 'hobby', 'fire balloon', redis.print);
client.hsetnx('user:7', 'spouse','Carl Fredricksen', redis.print);


client.hgetall('user:7', (err, obj) => {
    console.log('---------------');
    console.log(obj);
});

由於hobby已經存在，因此hooby資料不會被覆蓋

Output-TS

{
  name: 'Ellie Fredricksen',
  gender: 'F',
  age: '78',
  hobby: 'adventure'
}
---------------
Reply: 0
Reply: 1
---------------
{
  name: 'Ellie Fredricksen',
  gender: 'F',
  age: '78',
  hobby: 'adventure',
  spouse: 'Carl Fredricksen'
}