I have an object where Citems is an array of Object. Each object has status on or of and time.
{
Chapter: [
{
Cname: 'chapter 1',
Citems: [{status: 'on', time: 30},{status: 'on', time: 60}],
},
{
Cname: 'chapter 2',
Citems: [{status: 'on', time: 30},{status: 'off', time: 60}]
}
],
name: 'Something',
description: 'jfdgljfgdfjgldfkjglfd'
}
I want to generate an array or object from it that show total time for each status like below
{
on: 120,
off: 60
}
I tried with map and reduce but getting confused.
CodePudding user response:
You just need a nested 'sum', here implemented using reduce()
and making use of computed properties to update the accumulator using the status
as key.
const data = { Chapter: [{ Cname: 'chapter 1', Citems: [{ status: 'on', time: 30 }, { status: 'on', time: 60 }], }, { Cname: 'chapter 2', Citems: [{ status: 'on', time: 30 }, { status: 'off', time: 60 }] }], name: 'Something', description: 'jfdgljfgdfjgldfkjglfd' };
const result = data.Chapter.reduce((a, { Citems }) => {
for (const { status, time } of Citems) {
a[status] = time;
}
return a;
}, { on: 0, off: 0 });
console.log(result);
Or using a for...of
loop
const data = { Chapter: [{ Cname: 'chapter 1', Citems: [{ status: 'on', time: 30 }, { status: 'on', time: 60 }], }, { Cname: 'chapter 2', Citems: [{ status: 'on', time: 30 }, { status: 'off', time: 60 }] }], name: 'Something', description: 'jfdgljfgdfjgldfkjglfd' }
const result = { on: 0, off: 0 };
for (const { Citems } of data.Chapter) {
for (const { status, time } of Citems) {
result[status] = time;
}
}
console.log(result);
To extend this to an array of such Chapter
objects you could nest it once more in a reduce()
.
const data = [
{
Chapter: [{ Cname: 'chapter 1', Citems: [{ status: 'on', time: 30 }, { status: 'on', time: 60 }], }, { Cname: 'chapter 2', Citems: [{ status: 'on', time: 30 }, { status: 'off', time: 60 }] }],
name: 'Something',
description: 'jfdgljfgdfjgldfkjglfd'
},
{
Chapter: [{ Cname: 'chapter 1', Citems: [{ status: 'on', time: 30 }, { status: 'off', time: 30 }], }, { Cname: 'chapter 2', Citems: [{ status: 'on', time: 30 }, { status: 'off', time: 60 }] }],
name: 'Something2',
description: 'asdfasdfasdfasdfasdfa'
}
]
const result = data.reduce((a, { name, Chapter }) => {
a[name] = Chapter.reduce((a, { Citems }) => {
for (const { status, time } of Citems) {
a[status] = time;
}
return a;
}, { on: 0, off: 0 });
return a;
}, {});
console.log(result);
CodePudding user response:
let obj = {Chapter: [{_id: '624568b157da1d351910c576',Cname:'chapter 1',Citems: [{status: 'on',time: 30},{status: 'on',time: 60}],},{_id:'456a5857da1d351910c577',Cname: 'chapter 2',Citems: [{status:'on',time: 30},{status: 'off',time: 60}]}],_id: '6245f975d17514e0eb9092f7',name:'Something',description:'fdgljfgdfjgldfkjglfd'}
console.log(function() {
let on=0, off=0;
obj['Chapter'].forEach(function(elem) {
if (elem['Citems']) {
elem['Citems'].forEach(function(e) {
if (e['status'] == 'on') {on = e['time']} else if (e['status'] == 'off') {off = e['time']}
})
}
});
return {
on: on,
off: off
}
}())