I have an array of items
const test = [
{
id: '1',
},
{
id: 'a',
},
{
id: '3',
},
{
id: 'b',
},
{
id: '5',
},
{
id: 'c',
},
{
id: '7',
},
];
These objects are always going to be in the same order. I'd like to be able to remove all items in order from the start until a specific id is reached.
I thought I could do this by just looping through until one is found and then pushing the items coming after that to a separate array:
let skippedArray = []
let skipUntilIndex = undefined
test.forEach((item, i) => {
if(item.id === 'b') {
skipUntilIndex = i
}
if(skipUntilIndex && i >= skipUntilIndex) {
skippedArray.push(item)
}
})
// [
// {
// id: 'b',
// },
// {
// id: '5',
// },
// {
// id: 'c',
// },
// {
// id: '7',
// },
// ]
console.log(skippedArray)
But this seems pretty dirty. Is there a better way to achieve this? I don't mind using lodash or similar libraries.
You can do it by using findIndex and slice methods, by findIndex you can find the index of target item in the array and with slice you can make a subArray of your original Array.
const data = [ { id: '1', }, { id: 'a', }, { id: '3', }, { id: 'b', }, { id: '5', }, { id: 'c', }, { id: '7', }, ];
const getSkippedItems = (id)=> {
const index = data.findIndex(v => v.id == id);
return index > -1 ? data.slice(index) : [];
}
const skippedArr = getSkippedItems('b');
console.log(skippedArr)You can use Array.reduce() to filter out all items until our desired id is reached.
We'll only create the output array once we find the required id, then push remaining items into it.
const test = [ { id: '1' }, { id: 'a' }, { id: '3' }, { id: 'b' }, { id: '5' }, { id: 'c' }, { id: '7' } ];
const result = test.reduce((output, item) => {
if (!output && item.id === 'b') output = [];
if (output) output.push(item);
return output;
}, null);
console.log(result)
.as-console-wrapper { max-height: 100% !important; top: 0; }You could take a closure over a flag and if found filter the rest by found.
const
removeUntil = (id, found) => o => found ||= o.id === id,
test = [{ id: '1' }, { id: 'a' }, { id: '3' }, { id: 'b' }, { id: '5' }, { id: 'c' }, { id: '7' }],
result = test.filter(removeUntil('b'));
console.log(result);.as-console-wrapper { max-height: 100% !important; top: 0; }