搜索和更新嵌套在Javascript数组中的对象的属性

Question

Say I have an array of nested objects like

let vendors = [
    {
        v_id: 'red',
        count: 2,
    },
    {
        v_id: 'blue',
        count: 3,
    },
    {
        v_id: 'green',
        count: 1,
    },
];

And another object "foo" with many properties, one of which is "v_id". Based on the value of foo.v_id, I want to either update the counts in the "vendors" array or add a new object to "vendors".

If foo.v_id matches one of those in the "vendors" array, the corresponding count increases by 1.

Example:

let foo = {
    user_type: 'Other',
    v_id: 'blue'
};

Then "vendors" would become:

[
    {
        v_id: 'red',
        count: 2,
    },
    {
        v_id: 'blue',
        count: 4,
    },
    {
        v_id: 'green',
        count: 1,
    },
];

Else, if there is no match of v_id, a new object is added to the "vendors" array with the corresponding v_id & count = 1.

Example:

let foo = {
    user_type: 'client',
    v_id: 'yellow',
};

Then "vendors" would become:

[
    {
        v_id: 'red',
        count: 2,
    },
    {
        v_id: 'blue',
        count: 3,
    },
    {
        v_id: 'green',
        count: 1,
    },
    {
        v_id: 'yellow',
        count: 1,
    },
];

How can I efficiently & elegantly do this in Javascript? I know I can use .filter() to get the specific object in "vendors" that has to be updated but how would I update the "vendors" array itself?

Answer 1

Use Array.find() to search for the object in the array by v_id . If the object is in the array, increment count . If not push a new object:

 const vendors = [{"v_id":"red","count":2},{"v_id":"blue","count":3},{"v_id":"green","count":1}]; const foo1 = { user_type: 'Other', v_id: 'blue' }; const foo2 = { user_type: 'client', v_id: 'yellow' }; const addUpdate = (arr, obj) => { const current = arr.find((o) => o.v_id === obj.v_id); if(current) current.count += 1; else arr.push({ v_id: obj.v_id, count: 1 }); }; addUpdate(vendors, foo1); addUpdate(vendors, foo2); console.log(vendors); 

Answer 2

 function upsert(arr, obj){ const index = arr.findIndex(item => item.v_id === obj.v_id); index === -1 ? arr.push({v_id: obj.v_id, count: 1}) : arr[index].count++ } let vendors = [{v_id: 'red',count: 2}, {v_id: 'blue',count: 3}, {v_id: 'green',count: 1}]; let foo1 = {user_type: 'Other', v_id: 'blue'}; let foo2 = {user_type: 'client', v_id: 'yellow'}; upsert(vendors, foo1); upsert(vendors, foo2); console.log(vendors);