通过将数组的属性值与 angular/typescript 中的另一个数组进行比较来过滤数组

Question

I have two arrays

//1st one
tasks.push({ ID: 1, Address: "---", Latitude: 312313, Longitude: 21312 });
tasks.push({ ID: 3, Address: "---", Latitude: 312313, Longitude: 21312 });
//2nd one
agentTasks.push({ID:2,AgentID: 2,TaskID:1});

Now I want to filter tasks array to get only those values which are not included in agentTasks array. Like task id 1 is included in agentTasks but 3 is not included. So I want ID 3 value only. How can I do this in angular/typescript?

Answer 1

You could create a Set of all TaskIDs from agentTasks and then use .filter() on the tasks array to keep only those tasks which ID doesn't exist in the set of TaskIds:

 const tasks = [ { ID: 1, Address: "---", Latitude: 312313, Longitude: 21312 }, { ID: 3, Address: "---", Latitude: 312313, Longitude: 21312} ]; const agentTasks = [{ID:2,AgentID: 2,TaskID:1}]; const taskIds = new Set(agentTasks.map(({TaskID}) => TaskID)); const res = tasks.filter(({ID}) => !taskIds.has(ID)); console.log(res);

Answer 2

Ultimately you want to use the filter array function.

The simplest approach is to search the agentTasks array for each item in tasks . This is fine for small arrays, but inefficient for larger arrays.

Instead, I would create a Map from the agentTasks array, using TaskID as the key. You can then filter tasks based on whether or not they have a corresponding key in the Map .

 //1st one const tasks = []; tasks.push({ ID: 1, Address: "---", Latitude: 312313, Longitude: 21312 }); tasks.push({ ID: 3, Address: "---", Latitude: 312313, Longitude: 21312 }); //2nd one const agentTasks = []; agentTasks.push({ID:2,AgentID: 2,TaskID:1}); const agentTasksMap = new Map(agentTasks.map(x => [x.TaskID, x])); const filtered = tasks.filter(task => !agentTasksMap.has(task.ID)); console.log(filtered);

Edit: The answer using Set is better, since you don't care about the values in the Map in my answer - you only care about the existence of a key.