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Profile Lookup

Altcademy Team wrote on 7 February 2018

function lookUp(firstName, prop) { for (var i = 0; i < contacts.length; i++) { if (contacts[i].firstName === firstName && contacts[i][prop]) { return contacts[i][prop]; } else if (contacts[i][prop] === undefined) { return "No such property"; } else if (contacts[i].firstName === undefined) { return "No such contact"; } } }

I believe you are looking for this solution?
for (var i = 0; i < contacts.length; i++) { if (contacts[i].firstName === firstName) { if (contacts[i].hasOwnProperty(prop)) { return contacts[i][prop]; } else { return "No such property"; } } } return "No such contact";

为什么要在外层返回No such contact?

Answer
如果在内层返回,会过早返回,就是说还没有测试完全部的 contacts 前,就已决定没有 contact 的名字和 firstname 相符。

我们的目的是想知道 contacts 里有没有一个跟我们要找的名字一样,如果有,就看看他有没有我们找的 prop。如果有 prop ,就返回这个 prop 的函数,如果没有就返回 "No such property"。我们需要查看所有的 contacts 才能决定里面没有我们要找的 firstname。


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