method
Find the position(s) of an element in a list
Returns the index of matching elements inside a Redis list. By default, returns the index of the first match. Use RANK to find the nth occurrence, COUNT to get multiple positions, and MAXLEN to limit the search.
The list key
The element to search for
Optional arguments: "RANK", rank, "COUNT", num, "MAXLEN", len
Promise that resolves with the index (number), an array of indices (number[]), or null if element is not found. Returns array when COUNT option is used.
await redis.lpush("mylist", "a", "b", "c", "b", "d");
const pos1 = await redis.lpos("mylist", "b");
// pos1: 1 (first occurrence of "b")
const pos2 = await redis.lpos("mylist", "b", "RANK", 2);
// pos2: 3 (second occurrence of "b")
const positions = await redis.lpos("mylist", "b", "COUNT", 0);
// positions: [1, 3] (all occurrences of "b")
const pos3 = await redis.lpos("mylist", "x");
// pos3: null (element not found)