CODEWITHSUNDEEP
angulartypescript
nimgwfc
nimgwfc

Reputation: 1509

Angular filtering an array but excluding first element from filter

I have an array of objects that I am filtering. I don't want the first element in the array to be removed in the filter.

For example, the array (oData) may look like this:

[
 {id: "abc1", type: "car"},
 {id: "h445", type: "car"},
 {id: "kjj6", type: "van"},
 {id: "5yee", type: "bus"}
]

I'm applying a filter to remove elements where the type is in a list of user selected options as follows:

this.dataSet = this.oData.filter((d) => this.sOptions.includes(d.type));

If the user has selected 'van' and 'bus', the dataset looks like this:

[
 {id: "kjj6", type: "van"},
 {id: "5yee", type: "bus"}
]

However, I want the first element {id: "abc1", type: "car"} to always remain, i.e I want it to be excluded from the filter.

I have tried filtering and then using unShift() to add it back in but it is behaving strangely.

Is there a better way to do this?

Upvotes: 0

Views: 1372

Answers (3)

spots
spots

Reputation: 2708

There's a 2nd argument passed to the filter callback that represents the index of the current item. You can use to exclude the first element.

let data = [
 {id: "abc1", type: "car"},
 {id: "h445", type: "car"},
 {id: "kjj6", type: "van"},
 {id: "5yee", type: "bus"}
];

let selectedOptions = [
    "van",
    "bus"
]

let filtered = data.filter((item, idx) => {
    return idx === 0 || selectedOptions.indexOf(item.type) > -1;
});

console.log(JSON.stringify(filtered));
//PRINTS: [{"id":"abc1","type":"car"},{"id":"kjj6","type":"van"},{"id":"5yee","type":"bus"}]

Upvotes: 2

Rajdeep D
Rajdeep D

Reputation: 3920

In ES6, you can do it like this

var arr2 = this.oData.filter(a => a.type == "van" || a.type == "bus");
this.dataSet = [this.oData[0], ...arr2];

Upvotes: 0

Yair Cohen
Yair Cohen

Reputation: 2268

You could do it like this:

arr.filter(num => num !== arr[0] && yourConditionHere)

Upvotes: 1

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