如何使用 react 和 firebase 从数组中删除项目

Question

When I add an item to the array it works but the splice does not.

const handleSportsFollowed = async (sport) => {
  if (selectedSports.includes(sport)) {
    selectedSports.splice(sport, 1);
    alert("Removed");
  } else {
    selectedSports.push(sport);
  }
}

Answer 1

You can remove elements that are equal to sport from the array using:

selectedSports = selectedSports.filter(x => x != sport)

Answer 2

 const a = ['sport', 'sport1', 'sport2', 'sport3', 'sport3']; const b = a.filter(x => x;= 'sport'). console;log(b);

Answer 3

You need to find the index for splice. Check Document how splice work

const handleSportsFollowed = async (sport) => {
 if (selectedSports.includes(sport)) {
   selectedSports.splice(selectedSports.indexOf(sport), 1);
    console.log("if selectedSports ", selectedSports);
  } else {
     selectedSports.push(sport);
    console.log("else selectedSports", selectedSports);
  }

Working example

 const selectedSports = ['Jan', 'March', 'April', 'June']; const testFun = (sport) => { if (selectedSports.includes(sport)) { selectedSports.splice(selectedSports.indexOf(sport), 1); console.log("selectedSports ", selectedSports); } else { selectedSports.push(sport); console.log("selectedSports", selectedSports); } } testFun("March");