javascript LoDash _.has 用于多个键
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LoDash _.has for multiple keys
提问by YarGnawh
Is there a method or a chain of methods to check if an array of keys exists in an object available in lodash, rather than using the following?
是否有一种方法或一系列方法来检查 lodash 中可用的对象中是否存在一组键，而不是使用以下方法？
var params = {...}
var isCompleteForm = true;
var requiredKeys = ['firstname', 'lastname', 'email']
for (var i in requiredKeys) {
if (_.has(params, requiredKeys[i]) == false) {
isCompleteForm = false;
break;
}
}
if (isCompleteForm) {
// do something fun
}
UPDATE
更新
Thanks everyone for the awesome solutions! If you're interested, here's the jsPerf of the different solutions.
感谢大家的真棒解决方案！如果您有兴趣，这里是不同解决方案的 jsPerf。
回答by Allan Baptista
I know the question is about lodash, but this can be done with vanilla JS, and it is much faster:
我知道问题是关于 lodash 的，但这可以用 vanilla JS 来完成，而且速度要快得多：
requiredKeys.every(function(k) { return k in params; })
and even cleaner in ES2015:
甚至在 ES2015 中更干净：
requiredKeys.every(k => k in params)
回答by thefourtheye
You can totally go functional, with every, hasand partialfunctions, like this
你可以完全去功能性，与every，has和partial功能，这样
var requiredKeys = ['firstname', 'lastname', 'email'],
params = {
"firstname": "thefourtheye",
"lastname": "thefourtheye",
"email": "NONE"
};
console.log(_.every(requiredKeys, _.partial(_.has, params)));
// true
We pass a partial function object to _.every, which is actually _.haspartially applied to paramsobject. _.everywill iterate requiredKeysarray and pass the current value to the partial object, which will apply the current value to the partial _.hasfunction and will return trueor false. _.everywill return trueonly if all the elements in the array returns truewhen passed to the function object. In the example I have shown above, since all the keys are in params, it returns true. Even if a single element is not present in that, it will return false.
我们将一个部分函数对象传递给_.every，它实际上是_.has部分应用于params对象的。_.every将迭代requiredKeys数组并将当前值传递给部分对象，该对象会将当前值应用于部分_.has函数并返回trueor false。只有当数组中的所有元素在传递给函数对象时都返回时_.every才会返回。在我上面显示的示例中，由于所有键都在 中，因此它返回. 即使其中不存在单个元素，它也会返回.truetrueparamstruefalse
回答by djechlin
_(requiredKeys).difference(_(params).keys().value()).empty()
I believe. The key step is getting everything into arrays then working with sets.
我相信。关键步骤是将所有内容放入数组，然后使用集合。
or
或者
_requiredKeys.map(_.pluck(params).bind(_)).compact().empty()
Might work.
可能工作。
回答by irysius
Assuming that params can have more properties than is required...
假设 params 可以具有比所需更多的属性......
var keys = _.keys(params);
var isCompleteForm = requiredKeys.every(function (key) {
return keys.indexOf(key) != -1;
});
Should do the trick.
应该做的伎俩。
