I'm trying to add a property with a certain value to all of the objects in one array, based on a corresponding value in another array.
const array1 = [
{
id: 1,
date: '2022.05.01',
name: 'john'
}, {
id: 2,
date: '2022.05.01',
name: 'sam'
}, {
id: 3,
date: '2022.05.03',
name: 'john'
}, {
id: 4,
date: '2022.05.06',
name: 'jack'
},
]
This array contains the required modifications that need to be made:
const array2 = [
{
name: 'john',
isCanceled: true,
}, {
name: 'jack',
isCanceled: false,
}, {
name: 'sam',
isCanceled: false,
},
]
If the name in the object within array1 is john then isCanceled should be set to true, but if it's jack or sam it should be set to false like so:
const resultArray = [
{
id: 1,
date: '2022.05.01',
name: 'john',
isCanceled: true,
}, {
id: 2,
date: '2022.05.01',
name: 'sam'
isCanceled: false,
}, {
id: 3,
date: '2022.05.03',
name: 'john'
isCanceled: true,
}, {
id: 4,
date: '2022.05.06',
name: 'jack'
isCanceled: false,
},
];
Build a status lookup object containing the status, and map your array to include the matching values from the lookup object:
const status = Object.fromEntries(
array2.map(({name, isCanceled}) => [name, isCanceled])
);
const resultArray = array1.map(({id, date, name}) => ({
id,
date,
name,
isCanceled: status[name]
}));
Alternatively, if you just want to modify array1 instead of creating a new array, the second step can be replaced with:
array1.forEach(v => v.isCanceled = status[v.name]);
Complete snippet:
const array1 = [{
id: 1,
date: '2022.05.01',
name: 'john'
}, {
id: 2,
date: '2022.05.01',
name: 'sam'
}, {
id: 3,
date: '2022.05.03',
name: 'john'
}, {
id: 4,
date: '2022.05.06',
name: 'jack'
}, ];
const array2 = [{
name: 'john',
isCanceled: true,
}, {
name: 'jack',
isCanceled: false,
}, {
name: 'sam',
isCanceled: false,
}, ];
const status = Object.fromEntries(
array2.map(({name, isCanceled}) => [name, isCanceled])
);
const resultArray = array1.map(({id, date, name}) => ({
id,
date,
name,
isCanceled: status[name]
}));
console.log(resultArray);Should you wonder why I prefer to build the lookup object instead of using find() inside the map() operation: in terms of complexity, the lookup table has a complexity of O(1), while the find() approach is O(n).
you can do something as :
const result = array1.map(person => {
const lookPerson = array2.find(person2 => person2.name === person.name);
return (lookPerson) ? {
...person,
isCanceled: lookPerson.isCanceled
} : person;
});
combine array.map to transform array1
use array.find to get first iteration of similar person between array1 and array2
merge object with
{
...person,
isCanceled: lookPerson.isCanceled
}
const array1 = [{
id: 1,
date: '2022.05.01',
name: 'john'
}, {
id: 2,
date: '2022.05.01',
name: 'sam'
}, {
id: 3,
date: '2022.05.03',
name: 'john'
}, {
id: 4,
date: '2022.05.06',
name: 'jack'
}, ];
const array2 = [{
name: 'john',
isCanceled: true,
}, {
name: 'jack',
isCanceled: false,
}, {
name: 'sam',
isCanceled: false,
}, ];
const result = array1.map(person => {
const lookPerson = array2.find(person2 => person2.name === person.name);
return (lookPerson) ? {
...person,
isCanceled: lookPerson.isCanceled
} : person;
});
console.log(result);You can do this more simply by first converting your array2 into an object and then using a lookup within a map like so:
const array1 = [{id:1,date:"2022.05.01",name:"john"},{id:2,date:"2022.05.01",name:"sam"},{id:3,date:"2022.05.03",name:"john"},{id:4,date:"2022.05.06",name:"jack"},];
const array2 = [{name:"john",isCanceled:true},{name:"jack",isCanceled:false},{name:"sam",isCanceled:false}];
const arrCancel = array2.reduce((a, { name, isCanceled }) => {
a[name] = isCanceled;
return a;
}, {});
const resultArr = array1.map(e => {
e.isCanceled = arrCancel[e.name];
return e;
});
console.log(resultArr);.as-console-wrapper { max-height: 100% !important; top: auto; }