挑战:
所有的东西都是真的!
完善编辑器中的every函数,如果集合(collection)中的所有对象都存在对应的属性(第二个参数),并且属性(第二个参数)对应的值为真。函数返回ture。反之,返回false。
记住:您可以通过点符号或[]符号来访问对象属性。
例如:
every([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")
应该返回 true。
every([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")
应该返回 false。
every([{"user": "Tinky-Winky", "sex": "male", "age": 0}, {"user": "Dipsy", "sex": "male", "age": 3}, {"user": "Laa-Laa", "sex": "female", "age": 5}, {"user": "Po", "sex": "female", "age": 4}], "age")
应该返回 false。
every([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat")
应该返回 false
every([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat")
应该返回 true
every([{"single": "yes"}], "single")
应该返回 true
every([{"single": ""}, {"single": "double"}], "single")
应该返回 false
every([{"single": "double"}, {"single": undefined}], "single")
应该返回 false
every([{"single": "double"}, {"single": NaN}], "single")
应该返回 false
答案:
方法 | 描述 |
---|---|
every() | 检测数值元素的每个元素是否都符合条件。 |
function every(collection, pre) {
// Is everyone being true?
return collection.every(x => x[pre]);
}
every([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex");
运行结果:
true
在线测试: