如何从地图中计算布尔值

Question

使用的框架是 Angular 8

我有一个名为 teams 的数组，我可以使用 teams.length 来获取其中的长度。 现在teams 为每个计数都有一个名为teamInfo 的映射。这个 teamInfo 映射再次有一个布尔值 isClosed 可以通过 teams.teamInfo.isClosed 访问每个计数，当它被 jsoning 到 ngforloop 时，这是

*ngFor=" let teamID of JSObject.keys(teams); trackBy: trackByFn

<app-team-card
[team]="teams[teamID]"
[isClosed]="teams[teamID].teamInfo.isClosed">
</app-team-card>

我的目标是获取所有拥有isClosed =true.的地图的数量我的尝试是

getClosedTeams(teams) {
         let closedTeams = teams.teamInfo.filter((isClosed) => {
             return isClosed.select == true;
        });
        console.log(closedTeams.length);
    }

Answer 1

您可以使用.reduce 执行以下操作：

const team01 = new Map();
team01.set('name', 'team-01');
team01.set('isClosed', false);

const team02 = new Map();
team02.set('name', 'team-02');
team02.set('isClosed', true);

const team03 = new Map();
team03.set('name', 'team-01');
team03.set('isClosed', true);

const teams = [team01, team02, team03];

function getClosedTeamsCount (teams) {
  return teams.reduce((acc, teamInfo) => {
    return Number(teamInfo.get('isClosed')) + acc;
  }, 0)
}

console.log(getClosedTeamsCount(teams));