An array is given below. I would like to get the username for every single member of this array whose team is red!
const array = [
{
username: "john",
team: "red",
score: 5,
items: ["ball", "book", "pen"]
},
{
username: "becky",
team: "blue",
score: 10,
items: ["tape", "backpack", "pen"]
},
{
username: "susy",
team: "red",
score: 55,
items: ["ball", "eraser", "pen"]
},
{
username: "tyson",
team: "green",
score: 1,
items: ["book", "pen"]
},
];
I've tried this code:
const colorTeam = array.filter(teams=>teams.team === 'red');
console.log('teamColor:', username);
It didn't work!
As opposed to filter()
+ map()
(two passes over the source array), one may use Array.prototype.reduce()
to achieve that in a single pass (which may give certain performance gain should input array be large enough, or such filtering performed often enough):
const array = [{username:"john",team:"red",score:5,items:["ball","book","pen"]},{username:"becky",team:"blue",score:10,items:["tape","backpack","pen"]},{username:"susy",team:"red",score:55,items:["ball","eraser","pen"]},{username:"tyson",team:"green",score:1,items:["book","pen"]}], redTeamNames = array.reduce((acc, {username, team}) => (team == 'red' && acc.push(username), acc), []) console.log(redTeamNames)
.as-console-wrapper{min-height:100%;}
If this is what you wanted? First we filter objects with team === red
, then we map the array to contain username
property only.
const array = [ { username: "john", team: "red", score: 5, items: ["ball", "book", "pen"] }, { username: "becky", team: "blue", score: 10, items: ["tape", "backpack", "pen"] }, { username: "susy", team: "red", score: 55, items: ["ball", "eraser", "pen"] }, { username: "tyson", team: "green", score: 1, items: ["book", "pen"] }, ]; const colorTeam = array.filter(teams=>teams.team === 'red').map(user=>user.username); console.log('teamColor:', colorTeam);
user Array.filter
followed by Array.map
:
const array=[{username:"john",team:"red",score:5,items:["ball","book","pen"]},{username:"becky",team:"blue",score:10,items:["tape","backpack","pen"]},{username:"susy",team:"red",score:55,items:["ball","eraser","pen"]},{username:"tyson",team:"green",score:1,items:["book","pen"]}]; let result = array.filter(({team}) => team === "red").map(({username}) => username) console.log(result)
In one line:
let newArray = array.filter((el) => el.team==="red" ? el : "").map((el) => el.username);
First, filter objects with team property named "red", then use map method to get username properties only.
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