按属性在对象数组的数组中查找重复项的最短方法 [英] Shortest way to find duplicates in array of arrays of objects by property

问题描述

我有一个对象数组.每个对象都有一个对象数组.我需要查找在特定属性中具有相同值的(内部)对象的重复项.我决定在循环内创建一个循环并使用include.
有更短的方法吗?

Hi I have an array of objects. Each object has an array of objects. I need to find duplicates of (inner) objects that have the same value in a specific property. I made up to create a loop inside the loop and use include.
Is there a shorter way of doing this?

    // Verify that there are no duplicate device names.
    const streamItemNames = [];
    for (let i = 0, length1 = validateStreamItemsResults.streamWebSockets; i < length1; i++) {

        const streamItems = validateStreamItemsResults.streamWebSockets[i].streamItems;

        for (let y = 0, length2 = streamItems.length; y < length2; y++) {

            const streamItem = streamItems[i];
            const streamItemNameLower = streamItem.streamItemName.trim().toLowerCase();

            if (streamItemNames.includes(streamItemNameLower)) {
                validateStreamItemsResults.errorMessage = `Duplicate stream items found with the name: ${streamItemNameLower}`;
                return validateStreamItemsResults;
            } else {
                streamItemNames.push(streamItemNameLower);
            }
        }
    }

更新:
对象的结构如下，例如:
(我需要使用是或否来确定是否存在重复的"streamItemName"-在此示例中为-true).

UPDATE:
The structure of the objects is the following, for example:
(I need to determine with true or false if there are duplicates "streamItemName" - In the case of this example - true).

const childArray1 = [ { streamItemName: 'Name1' }, { streamItemName: 'Name2' }, { streamItemName: 'Name3' }, { streamItemName: 'Name4' }];
const childArray2 = [ { streamItemName: 'Name5' }, { streamItemName: 'Name6' }, { streamItemName: 'Name7' }, { streamItemName: 'Name1' }];
const parentArray = [childArray1, childArray2];

推荐答案

如果您正在寻找更清晰，更短的代码，则可以使用 flatMap 提取每个 streamItemName 放入单个数组中，然后使用 .find 查找是否存在重复项:

If you're looking for clearer, shorter code, you could use flatMap to extract every streamItemName into a single array, then use .find to find if there are any duplicates:

const streamItemNames = validateStreamItemsResults.streamWebSockets.flatMap(
  socket => socket.streamItems.map(
    item => item.streamItemName.trim().toLowerCase()
  )
);
const dupe = streamItemNames.find((name, i, arr) => arr.slice(i + 1).includes(name));
if (dupe) {
  validateStreamItemsResults.errorMessage = `Duplicate stream items found with the name: ${dupe}`;
  return validateStreamItemsResults;
}

如果您不需要知道重复的名称，则可以通过创建一个Set并将其 .size 与数组的 length进行比较来使其更短.

If you don't need to know the duplicate name, you could make it shorter by making a Set and comparing its .size against the array's length.

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