Type Error Angular : Undefined is not a function

Question

selectedProjectInfo is the data of selected project in which ProjectAssignedUsers and then, I got getemployeesList from API and then patch data with fields a and got this error.

I want to achieve if Id,s match in both list and I got name then this name on form filed

if(this.selectedProjectInfo.ProjectAssignedUsers)
this.selectedProjectInfo.ProjectAssignedUsers.forEach(
  this.getemployeesList.forEach((cacheEmployee: any) => {
    (backendAssignUser: any) => {
      if (
        cacheEmployee?.Id === backendAssignUser?.UserId &&
        backendAssignUser.UserAssignmentType === 1
      ) {
        this.salesRepList.push({
          FirstName: cacheEmployee?.FirstName,
          LastName: cacheEmployee?.LastName,
          UserTradeNames: cacheEmployee?.UserTradeNames,
          Id: cacheEmployee?.Id,
          UserAssignmentType: 1,

          Color: cacheEmployee?.Color,
        });
      } else if (
        cacheEmployee.Id === backendAssignUser.UserId &&
        backendAssignUser.UserAssignmentType === 2
      ) {
        this.estimatorsList.push({
          FirstName: cacheEmployee?.FirstName,
          LastName: cacheEmployee?.LastName,
          UserTradeNames: cacheEmployee?.UserTradeNames,
          Id: cacheEmployee?.Id,
          UserAssignmentType: 2,
          Color: cacheEmployee?.Color,
        });
      } else if (
        cacheEmployee.Id === backendAssignUser.UserId &&
        backendAssignUser.UserAssignmentType === 3
      ) {
        this.pmList.push({
          FirstName: cacheEmployee.FirstName,
          LastName: cacheEmployee.LastName,
          UserTradeNames: cacheEmployee.UserTradeNames,
          Id: cacheEmployee.Id,
          UserAssignmentType: 3,
          Color: cacheEmployee.Color,
        });
      }
    }
  }),

Answer 1

You have messed how you use forEach method on array.

this.selectedProjectInfo.ProjectAssignedUsers.forEach(
  this.getemployeesList.forEach((cacheEmployee: any) => {

Probably you want to make 1 nested iteration in the second forEach. In that case the correct way would be the following

 this.selectedProjectInfo.ProjectAssignedUsers.forEach(
      (projectAssignedUser: any) => {
        this.getemployeesList.forEach((cacheEmployee: any) => {
              .....
              .....
      }

Check the following simple example and see exactly the same error produced as it is in your code

var array1 = [1, 2];
var array2 = [3, 4, 5];

array1.forEach(
    array2.forEach((array2Element) => {
             console.log(array2Element);
             }));

While the following is the nested loop that you want and works

var array1 = [1, 2];
var array2 = [3, 4, 5];

array1.forEach((array1Element)=> {
    array2.forEach((array2Element) => {
             console.log(array2Element);
             })
});