Components: Angular Material Table Error - Cannot read property 'find' of undefined ...

[jmpreston]

Bug, feature request, or proposal:

Possible bug. Something changed in Angular Material 6 and was a breaking change for my project.

My table was working fine since it was introduced in Angular Material. I upgraded from Angular 5 to 6 and now I get this error when rendering the table:

TypeError: Cannot read property 'find' of undefined
at MatHeaderRowDef.ngOnChanges (table.js:47)

No data is yet loaded, a button does that. When I click the button:

TypeError: Cannot read property 'diff' of undefined
at MatRowDef.getColumnsDiff (table.js:57)

If I comment out a column then the error throws for the next column above it in the table so that all columns will produce this error, only one column at each render though.

The offending code in webpack:///./node_modules/@angular/cdk/esm2015/table.js:

    ngOnChanges(changes) {
        // Create a new columns differ if one does not yet exist. Initialize it based on initial value
        // of the columns property or an empty array if none is provided.
        const /** @type {?} */ columns = changes['columns'].currentValue || [];
        if (!this._columnsDiffer) {
Line 47:            this._columnsDiffer = this._differs.find(columns).create();
            this._columnsDiffer.diff(columns);
        }
    }

My table (shortened to two columns):

     <mat-table #table [dataSource]="dataSource" matSort>

        <ng-container matColumnDef="firstName">
          <mat-header-cell fxFlex="10%" *matHeaderCellDef> First Name </mat-header-cell>
          <mat-cell fxFlex="10%" *matCellDef="let row"> {{row.first_name}} </mat-cell>
        </ng-container>

        <ng-container matColumnDef="lastName">
          <mat-header-cell fxFlex="10%" *matHeaderCellDef mat-sort-header> Last Name </mat-header-cell>
          <mat-cell fxFlex="10%" *matCellDef="let row">  {{row.last_name}} </mat-cell>
        </ng-container>

       ...
        <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
        <mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>

     </mat-table>

    <mat-paginator #paginator
                   [pageIndex]="0"
                   [pageSize]="5"
                   [pageSizeOptions]="[5, 10, 25, 100]">
    </mat-paginator>

In the component.ts file:

import { MatPaginator, MatSort, MatTableDataSource } from '@angular/material';

  private displayedColumns = [
    'firstName',
    'lastName',
    ...
    ];

    ngAfterViewInit() {
      this.dataSource.paginator = this.paginator;
    }

What is the expected behavior?

Table should compile with this error.

What is the current behavior?

The problem may be related to this closed issue but a bit different:
https://github.com/angular/material2/issues/6831

What are the steps to reproduce?

My first try with Stackblitz, never used Plunker, so probably something wrong. I shortened my code to just the problem code for the table. The error message goes away if I comment out the table. Other items on the page such as search don't affect this.

https://stackblitz.com/edit/angular-material2-issue-yp6jrt

What is the use-case or motivation for changing an existing behavior?

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Angular CLI: 6.0.3
Node: 8.11.2
OS: darwin x64
Angular: 6.0.2
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.6.3
@angular-devkit/build-angular     0.6.3
@angular-devkit/build-optimizer   0.6.3
@angular-devkit/core              0.6.3
@angular-devkit/schematics        0.6.3
@angular/cdk                      6.0.0
@angular/cli                      6.0.3
@angular/flex-layout              6.0.0-beta.15
@angular/material                 6.0.0
@ngtools/webpack                  6.0.3
@schematics/angular               0.6.3
@schematics/update                0.6.3
rxjs                              6.1.0
typescript                        2.7.2
webpack                           4.8.3

Is there anything else we should know?

I followed upgrade.angular.io and used these magic lines in terminal:

npm install -g rxjs-tslint
rxjs-5-to-6-migrate -p src/tsconfig.app.json

I don't see how this could have affected my table. I suspect that something was changed for AM 6 and is causing a bug under some circumstances. My setup seems rather typical though.

[andrewseguin]

This is due to an issue with how the Angular compiler was compiling our ES6 version. This should be fixed in the next patch release. See #9329 for details

Also, thanks for diving into the code and finding the offending line. That helped saved me a lot of time understanding the issue

[jmpreston]

Thanks @andrewseguin for being on top of this! My table is the core of my app and not much dev work can be done until it renders. Rather stuck.

[andrewseguin]

@svstartuplab Keep an eye out today or tomorrow for our next patch release 6.0.3 which should resolve the issue and get you unstuck

[jmpreston]

Thanks @andrewseguin, the issue is fixed :-)

[andrewseguin]

Glad to hear it! Thanks for verifying

[Narrator]

Hello, I'm pretty sure this issue is back with the release of 6.4.2.. i verified this by changing the @angular/material package from 6.4.1 to 6.4.2. I don't get the error with 6.4.1, but I do with 6.4.2.

Here's my html:

<div class="mat-elevation-z2 usersContainer" *ngIf="datasource && datasource.data && datasource.data.length > 0">
  <table mat-table [dataSource]="datasource" style="text-align:center">

      <ng-container matColumnDef="name">
        <th mat-header-cell *matHeaderCellDef> Name </th>
        <td mat-cell *matCellDef="let element" class="name"> {{ element.firstName }} {{ element.lastName }} </td>
      </ng-container>

      <ng-container matColumnDef="email">
        <th mat-header-cell *matHeaderCellDef> E-mail </th>
        <td mat-cell *matCellDef="let element" class="email"> {{element.email}} </td>
      </ng-container>

      <ng-container matColumnDef="role">
        <th mat-header-cell *matHeaderCellDef> Role </th>
        <td mat-cell style="text-transform: capitalize;" *matCellDef="let element" class="role"> {{ resolveRole(element.roleId) }} </td>
      </ng-container>

      <ng-container matColumnDef="edit">
        <th mat-header-cell *matHeaderCellDef> Edit </th>
        <td mat-cell *matCellDef="let element" class="edit">
          <button class="edit-button" (click)="editProfile(element)" mat-button >
            <mat-icon>
              create
            </mat-icon> Edit
          </button>
        </td>
      </ng-container>

      <ng-container matColumnDef="remove">
          <th mat-header-cell *matHeaderCellDef> Remove </th>
          <td mat-cell *matCellDef="let element" class="rempve">
            <button class="remove-button" (click)="removeUser(element)" mat-button >
              <mat-icon>
                delete
              </mat-icon> Remove
            </button>
          </td>
      </ng-container>

      <ng-container matColumnDef="verified">
        <th mat-header-cell *matHeaderCellDef class="verified"> Verified </th>
        <td mat-cell *matCellDef="let element">

          <button *ngIf="element.verified" class="verified-button" mat-button disabled>
              <mat-icon>
                verified_user
              </mat-icon> Verified
          </button>

          <button *ngIf="!element.verified" class="send-button" (click)="resendEmail(element)" mat-button>
              <mat-icon>
                email
              </mat-icon> Resend
          </button>
        </td>
      </ng-container>


      <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
      <tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
    </table>

    <mat-paginator [pageSizeOptions]="[15, 10, 20]" showFirstLastButtons></mat-paginator>
</div>

<div class="no-users" *ngIf="!datasource || !datasource.data || datasource.data.length < 1">
  <div class="no-content-text">
    <mat-icon>person_pin</mat-icon><br><br>
    Use the add button to register users.
  </div>
</div>

And my component's ngOnInit:

public ngOnInit() {
    this._userApi.getAllUsers()
      .pipe(takeUntil(this._unsubscribe))
      .subscribe({
        next: users => {
          this.users = users;
          this.datasource = new MatTableDataSource<TransitApi.User>(this.users);
          this.datasource.paginator = this.paginator;
        },
        error: err => {
          this._snackbar.open('Error loading user list.');
        }
      });
}

[hvdscheer]

Same here V6.4.1 is working. V6.4.2 and V6.4.3 throws an error:

ERROR TypeError: Cannot read property 'find' of undefined
at MatHeaderRowDef.ngOnChanges (table.js:324)
at MatHeaderRowDef.ngOnChanges (table.js:376)
at checkAndUpdateDirectiveInline (core.js:11642)
at checkAndUpdateNodeInline (core.js:13252)
at checkAndUpdateNode (core.js:13191)
at debugCheckAndUpdateNode (core.js:14147)
at debugCheckDirectivesFn (core.js:14090)
at Object.eval [as updateDirectives] (ShoppingListComponent.html:11)
at Object.debugUpdateDirectives [as updateDirectives] (core.js:14078)
at checkAndUpdateView (core.js:13156)

HTML:
<mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>

[jmpreston]

hvdscheer, you have a coding error. A var isn't being populated with data so it is undefined.

[RyanHayden]

I was receiving the same error and reverting back to 6.4.1 (angular/material and angular/cdk) fixed this for me. Was on 6.4.5

[hvdscheer]

Although the error stack trace leads to my own component the error is thrown in the material code. The "displayedColumns" is a hardcoded string array in my code. Again, in 6.4.1 everything is working fine. When i upgrade to 6.4.2 or 6.4.3 this error occurs.
public displayedColumns: string[] = ['name', 'numberOfProducts'];

[MauricioArroyo]

6.4.6, still an issue. Revert to 6.4.1 as it's suggested fixed the problem.

[charlesritchea]

@andrewseguin Please re-open this issue, it is no longer fixed

[andzejsw]

Reverting back versions cannot ever be considered as fix. So issue should be reopened, until it is working on latest versions!

[andrewseguin]

Sorry guys, this is something that needs to be fixed in Angular. See this issue for its status: https://github.com/angular/angular/issues/27267

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