[英]Javascript Array sorting unique object with a key value condition
我有一个数组
"datawithisNew": [
{
"exam_name": "MPSC",
"isNew": false
},
{
"exam_name": "MPSC",
"isNew": true
},
{
"exam_name": "UPSC",
"isNew": false
},
{
"exam_name": "RAILWAY",
"isNew": false
},
{
"exam_name": "RAILWAY",
"isNew": false
}]
我想获得独特的结果exam_name
这样的对象,导致阵列保存唯一exam_name
值也如果exam_name
有ATLEAST 1个isNew
键为真,将产生的对象应该具有与物业isNew
true
,如果不是false
。 预期结果——
"datawithisNew": [
{
"exam_name": "MPSC",
"isNew": true
},
{
"exam_name": "UPSC",
"isNew": false
},
{
"exam_name": "RAILWAY",
"isNew": false
}]
我使用的代码是-
var helper1 = {};
var result2 = data12.reduce(function(r, o) {
var key = o.exam_name ;
if(!helper1[key]) {
helper1[key] = Object.assign({}, o); // create a copy of o
r.push(helper1[key]);
} else {
helper1[key].exam_name_rating += o.exam_name_rating;
}
return r;
}, []);
但是,这只是返回唯一的exam_name
对象我还需要isNew
如果发生ATLEAST其关键true
ATLEAST一次的exam_name
它应该有isNew:true
为真或者isNew:false
使用 JS Array.filter
过滤掉重复项
const datawithisNew = [{ "exam_name": "MPSC", "isNew": false }, { "exam_name": "MPSC", "isNew": true }, { "exam_name": "UPSC", "isNew": false }, { "exam_name": "RAILWAY", "isNew": false }, { "exam_name": "RAILWAY", "isNew": false } ]; const uniqueItems = datawithisNew.filter((exam, index, self) => { return self.findIndex(e => exam.exam_name === e.exam_name) === index }).map(exam => { if (!exam.isNew && datawithisNew.find(e => e.exam_name === exam.exam_name && e.isNew)) { exam.isNew = true; } return exam; }); console.log(uniqueItems);
使用您的 datawithisNew 作为参数调用下面的函数
function getUniqueExams(data){
let finalObjMap = { };
for(var i=0;i<data.length;i++){
let currentObj = data[i];
if(finalObjMap[currentObj["exam_name"]])
{
if(!finalObjMap[currentObj["isNew"]] && currentObj["isNew"])
finalObjMap[currentObj["exam_name"]]["isNew"]=true;
}
else
{
finalObjMap[currentObj["exam_name"]]={"isNew":currentObj["isNew"]};
}
}
let finalData=[];
Object.keys(finalObjMap).forEach((key)=>{
let tempExamObj = { "exam_name": key , "isNew": finalObjMap[key]["isNew"]};
finalData.push(tempExamObj);
});
return finalData;
};
var datawithisNew=[
{
"exam_name": "MPSC",
"isNew": false
},
{
"exam_name": "MPSC",
"isNew": true
},
{
"exam_name": "UPSC",
"isNew": false
},
{
"exam_name": "RAILWAY",
"isNew": false
},
{
"exam_name": "RAILWAY",
"isNew": false
}];
console.log(getUniqueExams(datawithisNew));
您离实际解决方案不远,添加以下行可以解决您的问题:
helper1[key].isNew ||= o.isNew;
如果当前值为假, ||=
会将变量或属性分配给一个值。
如果您不能使用逻辑 OR 赋值( ||=
) 运算符,因为它是一个相当新的赋值运算符,您可以使用:
if (!helper1[key].isNew) helper1[key].isNew = o.isNew;
const data12 = [ { "exam_name": "MPSC", "isNew": false }, { "exam_name": "MPSC", "isNew": true }, { "exam_name": "UPSC", "isNew": false }, { "exam_name": "RAILWAY", "isNew": false }, { "exam_name": "RAILWAY", "isNew": false }, ]; var helper1 = {}; var result2 = data12.reduce(function(r, o) { var key = o.exam_name ; if(!helper1[key]) { helper1[key] = Object.assign({}, o); // create a copy of o r.push(helper1[key]); } else { helper1[key].exam_name_rating += o.exam_name_rating; helper1[key].isNew ||= o.isNew; // <- added this line } return r; }, []); console.log(result2);
由于示例数据不包含exam_name_rating
属性,它将丢失,或者结果设置为NaN
。 我假设此属性在您自己的数据中可用。
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