I have an array, that contains another arrays with string id's. I need to get an array with string ids, that are exists in all arrays of parent.
Here is example:
const parentArray = [ ['test1', 'test2', 'test3'], ['test2', 'test4', 'test5'], ['test3', 'test2', 'test6']];
//some magic. Maybe use lodash instersection func
console.log(result) => ['test2']
Important note! I don't know, how much arrays of elements in parent array, thats the problem that i cant understand how to use lodash intersection function:(
const parentArray = [ ['test1', 'test2', 'test3'], ['test2', 'test4', 'test5'], ['test3', 'test2', 'test6']];
let common = parentArray.reduce((p,c) => p.filter(e => c.includes(e)));
// ['test2']
The below may be one possible way to achieve the desired result.
Code Sample
const commonElements = (arr1, arr2) => (
arr1.length === 0
? arr2
: [...(new Set([...arr1, ...arr2]))]
.filter(
x => arr1.includes(x) && arr2.includes(x)
)
);
const intersectAllElements = (arr = parentArray) => (
arr.reduce(
(fin, itm) => (commonElements(fin, itm)),
[]
)
);
Explanation
commonElements that will share either common elements between 2 arrays, or if the first array is empty then the second arrayparentArray using .reducefin as an empty arrayparentArray, track the common elements between the aggregator and given itemCode Snippet
const parentArray = [ ['test1', 'test2', 'test3'], ['test2', 'test4', 'test5'], ['test3', 'test2', 'test6']];
const commonElements = (arr1, arr2) => (
arr1.length === 0
? arr2
: [...(new Set([...arr1, ...arr2]))]
.filter(
x => arr1.includes(x) && arr2.includes(x)
)
);
const intersectAllElements = (arr = parentArray) => (
arr.reduce(
(fin, itm) => (commonElements(fin, itm)),
[]
)
);
console.log(intersectAllElements());Lodash solution:
const parentArray=[["test1","test2","test3"],["test2","test4","test5"],["test3","test2","test6"]];
const result = parentArray.reduce((acc, arr) => _.intersection(acc, arr));
console.log(result);.as-console-wrapper{min-height: 100%!important; top: 0}<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.21/lodash.min.js"></script>