如果数组中的任何一项为true或false，如何获取布尔值

Question

我有这个数组，它是用户生成的，随着时间的推移而变化：

const data = [["2020-09-14","15:00","60","Info","April Tucker","Other","yes"],
["2020-09-14","2:00","50","Text","April Tucker","Other","yes"]]

用户选择保存到会话存储的日期(例如：2020-11-21(：sessionStorage.getItem('date')

然后我使用forEach方法来知道数组项的第一个项是否具有相同的值：

const checkForConflicts = () => {
mydata.forEach((element) => {
element.includes(sessionStorage.getItem('date'))
})
}

如果我控制台日志，我得到数组中所有项的布尔值。如何只返回一个布尔值，如果checkForConflict只返回false值，则返回true，如果返回alt至少一个true值，则为false。

Answer 1

可能是Array.prototype.every或Array.prototype.some中的一个，甚至两者都会为您带来合适的工具。

简化示例代码。。。

const data = [
["2020-09-14","15:00","60","Info","April Tucker","Other","yes"],
["2020-09-14","2:00","50","Text","April Tucker","Other","yes"]
];
console.log(
'data.every(item => item[0] === "2020-09-14") ? ',
data.every(item => item[0] === "2020-09-14")
);
console.log(
'data.some(item => item[0] === "2020-09-14") ? ',
data.some(item => item[0] === "2020-09-14")
);
data.push(
["2020-09-15","2:00","50","Text","April Tucker","Other","yes"]
);
console.log(
'data.every(item => item[0] === "2020-09-14") ? ',
data.every(item => item[0] === "2020-09-14")
);
console.log(
'data.some(item => item[0] === "2020-09-14") ? ',
data.some(item => item[0] === "2020-09-14")
);

.as-console-wrapper { min-height: 100%!important; top: 0; }

Answer 2

尝试some((方法：

const checkForConflicts = () => {
mydata.forEach((element) => {
element.some(!sessionStorage.getItem('date'))
})
}

Answer 3

好吧，你不需要在数据上使用forEach和循环你可以找到冲突项目的索引-1意味着它们没有冲突

const checkForConflicts = () => {
return data.findIndex((element) => {
element.includes(sessionStorage.getItem('date'))
}) !== -1;
}

最重要的是，您必须在函数中返回值。

Answer 4

我建议使用一个对象数组，如果不是，请修改此代码以查看数组中的第一个元素。注意，我用一个local代替了我的测试，以一种简单的方式在这里显示它，而不是sessionStorage

const data = [{
date: "2020-09-14",
time: "15:00",
somenumber: "60",
cheers: "Info",
name: "April Tucker",
"note": "Other",
says: "yes"
},
{
date: "2020-09-14",
time: "15:00",
somenumber: "60",
cheers: "Info",
name: "Fred Tucker",
"note": "Other",
says: "yes"
},
{
date: "2020-09-13",
time: "2:00",
somenumber: "50",
cheers: "Text",
name: "April Tucker",
"note": "Other",
says: "yes"
}
];
let testdate = "2020-09-14";
let testdate2 = "2020-09-19";
const checkForConflicts = (item, testme) => {
// compare as dates to forgive formatting etc.
return (new Date(item).getTime() === new Date(testme).getTime())
};
// I used .filter in case you need to know how many conflicts but .some() might work also
let hasConflict = !!data.filter(x => checkForConflicts(x.date, testdate)).length;
console.log(hasConflict);
let conflictCount = data.filter(x => checkForConflicts(x.date, testdate)).length;
console.log(conflictCount);
let hasConflict2 = !!data.filter(x => checkForConflicts(x.date, testdate2)).length;
console.log(hasConflict2);