diff --git a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
index 086d817..b96ec2c 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
@@ -14,206 +14,219 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../../../styles/gr-menu-page-styles.js';
-import '../../../styles/gr-subpage-styles.js';
-import '../../../styles/shared-styles.js';
-import '../../shared/gr-rest-api-interface/gr-rest-api-interface.js';
-import '../gr-access-section/gr-access-section.js';
-import {flush} from '@polymer/polymer/lib/legacy/polymer.dom.js';
-import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners.js';
-import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin.js';
-import {PolymerElement} from '@polymer/polymer/polymer-element.js';
-import {htmlTemplate} from './gr-repo-access_html.js';
+import '../../../styles/gr-menu-page-styles';
+import '../../../styles/gr-subpage-styles';
+import '../../../styles/shared-styles';
+import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
+import '../gr-access-section/gr-access-section';
+import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
+import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
+import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
+import {PolymerElement} from '@polymer/polymer/polymer-element';
+import {htmlTemplate} from './gr-repo-access_html';
+import {encodeURL, getBaseUrl, singleDecodeURL} from '../../../utils/url-util';
+import {GerritNav} from '../../core/gr-navigation/gr-navigation';
+import {toSortedPermissionsArray} from '../../../utils/access-util';
+import {customElement, property} from '@polymer/decorators';
 import {
-  encodeURL,
-  getBaseUrl,
-  singleDecodeURL,
-} from '../../../utils/url-util.js';
-import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
-import {toSortedPermissionsArray} from '../../../utils/access-util.js';
-
-const Defs = {};
+  RepoName,
+  ProjectInfo,
+  CapabilityInfoMap,
+  LabelNameToLabelTypeInfoMap,
+  ProjectAccessInput,
+  GitRef,
+  UrlEncodedRepoName,
+  ProjectAccessGroups,
+} from '../../../types/common';
+import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
+import {hasOwnProperty} from '../../../utils/common-util';
+import {GrButton} from '../../shared/gr-button/gr-button';
+import {GrAccessSection} from '../gr-access-section/gr-access-section';
+import {
+  AutocompleteQuery,
+  AutocompleteSuggestion,
+} from '../../shared/gr-autocomplete/gr-autocomplete';
+import {
+  EditableLocalAccessSectionInfo,
+  PermissionAccessSection,
+  PropertyTreeNode,
+  PrimitiveValue,
+} from './gr-repo-access-interfaces';
 
 const NOTHING_TO_SAVE = 'No changes to save.';
 
 const MAX_AUTOCOMPLETE_RESULTS = 50;
 
+export interface GrRepoAccess {
+  $: {
+    restAPI: RestApiService & Element;
+  };
+}
+
 /**
  * Fired when save is a no-op
  *
  * @event show-alert
  */
+@customElement('gr-repo-access')
+export class GrRepoAccess extends GestureEventListeners(
+  LegacyElementMixin(PolymerElement)
+) {
+  static get template() {
+    return htmlTemplate;
+  }
 
-/**
- * @typedef {{
- *    value: !Object,
- * }}
- */
-Defs.rule;
+  @property({type: String, observer: '_repoChanged'})
+  repo?: RepoName;
 
-/**
- * @typedef {{
- *    rules: !Object<string, Defs.rule>
- * }}
- */
-Defs.permission;
+  @property({type: String})
+  path?: string;
 
-/**
- * Can be an empty object or consist of permissions.
- *
- * @typedef {{
- *    permissions: !Object<string, Defs.permission>
- * }}
- */
-Defs.permissions;
+  @property({type: Boolean})
+  _canUpload?: boolean = false; // restAPI can return undefined
 
-/**
- * Can be an empty object or consist of permissions.
- *
- * @typedef {!Object<string, Defs.permissions>}
- */
-Defs.sections;
+  @property({type: String})
+  _inheritFromFilter?: RepoName;
 
-/**
- * @typedef {{
- *    remove: !Defs.sections,
- *    add: !Defs.sections,
- * }}
- */
-Defs.projectAccessInput;
+  @property({type: Object})
+  _query: AutocompleteQuery;
 
-/**
- * @extends PolymerElement
- */
-class GrRepoAccess extends GestureEventListeners(
-    LegacyElementMixin(
-        PolymerElement)) {
-  static get template() { return htmlTemplate; }
+  @property({type: Array})
+  _ownerOf?: GitRef[];
 
-  static get is() { return 'gr-repo-access'; }
+  @property({type: Object})
+  _capabilities?: CapabilityInfoMap;
 
-  static get properties() {
-    return {
-      repo: {
-        type: String,
-        observer: '_repoChanged',
-      },
-      // The current path
-      path: String,
+  @property({type: Object})
+  _groups?: ProjectAccessGroups;
 
-      _canUpload: {
-        type: Boolean,
-        value: false,
-      },
-      _inheritFromFilter: String,
-      _query: {
-        type: Function,
-        value() {
-          return this._getInheritFromSuggestions.bind(this);
-        },
-      },
-      _ownerOf: Array,
-      _capabilities: Object,
-      _groups: Object,
-      /** @type {?} */
-      _inheritsFrom: Object,
-      _labels: Object,
-      _local: Object,
-      _editing: {
-        type: Boolean,
-        value: false,
-        observer: '_handleEditingChanged',
-      },
-      _modified: {
-        type: Boolean,
-        value: false,
-      },
-      _sections: Array,
-      _weblinks: Array,
-      _loading: {
-        type: Boolean,
-        value: true,
-      },
-    };
+  @property({type: Object})
+  _inheritsFrom?: ProjectInfo | null | {};
+
+  @property({type: Object})
+  _labels?: LabelNameToLabelTypeInfoMap;
+
+  @property({type: Object})
+  _local?: EditableLocalAccessSectionInfo;
+
+  @property({type: Boolean, observer: '_handleEditingChanged'})
+  _editing = false;
+
+  @property({type: Boolean})
+  _modified = false;
+
+  @property({type: Array})
+  _sections?: PermissionAccessSection[];
+
+  @property({type: Array})
+  _weblinks?: string[];
+
+  @property({type: Boolean})
+  _loading = true;
+
+  private _originalInheritsFrom?: ProjectInfo | null;
+
+  constructor() {
+    super();
+    this._query = () => this._getInheritFromSuggestions();
   }
 
   /** @override */
   created() {
     super.created();
-    this.addEventListener('access-modified',
-        () =>
-          this._handleAccessModified());
+    this.addEventListener('access-modified', () =>
+      this._handleAccessModified()
+    );
   }
 
   _handleAccessModified() {
     this._modified = true;
   }
 
-  /**
-   * @param {string} repo
-   * @return {!Promise}
-   */
-  _repoChanged(repo) {
+  _repoChanged(repo: RepoName) {
     this._loading = true;
 
-    if (!repo) { return Promise.resolve(); }
+    if (!repo) {
+      return Promise.resolve();
+    }
 
     return this._reload(repo);
   }
 
-  _reload(repo) {
-    const promises = [];
-
-    const errFn = response => {
-      this.dispatchEvent(new CustomEvent('page-error', {
-        detail: {response},
-        composed: true, bubbles: true,
-      }));
+  _reload(repo: RepoName) {
+    const errFn = (response?: Response | null) => {
+      this.dispatchEvent(
+        new CustomEvent('page-error', {
+          detail: {response},
+          composed: true,
+          bubbles: true,
+        })
+      );
     };
 
     this._editing = false;
 
     // Always reset sections when a project changes.
     this._sections = [];
-    promises.push(this.$.restAPI.getRepoAccessRights(repo, errFn)
-        .then(res => {
-          if (!res) { return Promise.resolve(); }
+    const sectionsPromises = this.$.restAPI
+      .getRepoAccessRights(repo, errFn)
+      .then(res => {
+        if (!res) {
+          return Promise.resolve(undefined);
+        }
 
-          // Keep a copy of the original inherit from values separate from
-          // the ones data bound to gr-autocomplete, so the original value
-          // can be restored if the user cancels.
-          this._inheritsFrom = res.inherits_from ? ({
-            ...res.inherits_from}) : null;
-          this._originalInheritsFrom = res.inherits_from ? ({
-            ...res.inherits_from}) : null;
-          // Initialize the filter value so when the user clicks edit, the
-          // current value appears. If there is no parent repo, it is
-          // initialized as an empty string.
-          this._inheritFromFilter = res.inherits_from ?
-            this._inheritsFrom.name : '';
-          this._local = res.local;
-          this._groups = res.groups;
-          this._weblinks = res.config_web_links || [];
-          this._canUpload = res.can_upload;
-          this._ownerOf = res.owner_of || [];
-          return toSortedPermissionsArray(this._local);
-        }));
+        // Keep a copy of the original inherit from values separate from
+        // the ones data bound to gr-autocomplete, so the original value
+        // can be restored if the user cancels.
+        this._inheritsFrom = res.inherits_from
+          ? {
+              ...res.inherits_from,
+            }
+          : null;
+        this._originalInheritsFrom = res.inherits_from
+          ? {
+              ...res.inherits_from,
+            }
+          : null;
+        // Initialize the filter value so when the user clicks edit, the
+        // current value appears. If there is no parent repo, it is
+        // initialized as an empty string.
+        this._inheritFromFilter = res.inherits_from
+          ? res.inherits_from.name
+          : ('' as RepoName);
+        // 'as EditableLocalAccessSectionInfo' is required because res.local
+        // type doesn't have index signature
+        this._local = res.local as EditableLocalAccessSectionInfo;
+        this._groups = res.groups;
+        this._weblinks = res.config_web_links || [];
+        this._canUpload = res.can_upload;
+        this._ownerOf = res.owner_of || [];
+        return toSortedPermissionsArray(this._local);
+      });
 
-    promises.push(this.$.restAPI.getCapabilities(errFn)
-        .then(res => {
-          if (!res) { return Promise.resolve(); }
+    const capabilitiesPromises = this.$.restAPI
+      .getCapabilities(errFn)
+      .then(res => {
+        if (!res) {
+          return Promise.resolve(undefined);
+        }
 
-          return res;
-        }));
+        return res;
+      });
 
-    promises.push(this.$.restAPI.getRepo(repo, errFn)
-        .then(res => {
-          if (!res) { return Promise.resolve(); }
+    const labelsPromises = this.$.restAPI.getRepo(repo, errFn).then(res => {
+      if (!res) {
+        return Promise.resolve(undefined);
+      }
 
-          return res.labels;
-        }));
+      return res.labels;
+    });
 
-    return Promise.all(promises).then(([sections, capabilities, labels]) => {
+    return Promise.all([
+      sectionsPromises,
+      capabilitiesPromises,
+      labelsPromises,
+    ]).then(([sections, capabilities, labels]) => {
       this._capabilities = capabilities;
       this._labels = labels;
       this._sections = sections;
@@ -221,33 +234,42 @@
     });
   }
 
-  _handleUpdateInheritFrom(e) {
+  _handleUpdateInheritFrom(e: CustomEvent<{value: string}>) {
+    const parentProject: ProjectInfo = {
+      id: e.detail.value as UrlEncodedRepoName,
+      name: this._inheritFromFilter,
+    };
     if (!this._inheritsFrom) {
-      this._inheritsFrom = {};
+      this._inheritsFrom = parentProject;
+    } else {
+      // TODO(TS): replace with
+      // this._inheritsFrom = {...this._inheritsFrom, ...parentProject};
+      const projectInfo = this._inheritsFrom as ProjectInfo;
+      projectInfo.id = parentProject.id;
+      projectInfo.name = parentProject.name;
     }
-    this._inheritsFrom.id = e.detail.value;
-    this._inheritsFrom.name = this._inheritFromFilter;
     this._handleAccessModified();
   }
 
-  _getInheritFromSuggestions() {
-    return this.$.restAPI.getRepos(
-        this._inheritFromFilter,
-        MAX_AUTOCOMPLETE_RESULTS)
-        .then(response => {
-          const projects = [];
-          for (const key in response) {
-            if (!response.hasOwnProperty(key)) { continue; }
-            projects.push({
-              name: response[key].name,
-              value: response[key].id,
-            });
-          }
+  _getInheritFromSuggestions(): Promise<AutocompleteSuggestion[]> {
+    return this.$.restAPI
+      .getRepos(this._inheritFromFilter, MAX_AUTOCOMPLETE_RESULTS)
+      .then(response => {
+        const projects: AutocompleteSuggestion[] = [];
+        if (!response) {
           return projects;
-        });
+        }
+        for (const item of response) {
+          projects.push({
+            name: item.name,
+            value: item.id,
+          });
+        }
+        return projects;
+      });
   }
 
-  _computeLoadingClass(loading) {
+  _computeLoadingClass(loading: boolean) {
     return loading ? 'loading' : '';
   }
 
@@ -255,27 +277,37 @@
     this._editing = !this._editing;
   }
 
-  _editOrCancel(editing) {
+  _editOrCancel(editing: boolean) {
     return editing ? 'Cancel' : 'Edit';
   }
 
-  _computeWebLinkClass(weblinks) {
+  _computeWebLinkClass(weblinks?: string[]) {
     return weblinks && weblinks.length ? 'show' : '';
   }
 
-  _computeShowInherit(inheritsFrom) {
+  _computeShowInherit(inheritsFrom?: RepoName) {
     return inheritsFrom ? 'show' : '';
   }
 
-  _handleAddedSectionRemoved(e) {
-    const index = e.model.index;
-    this._sections = this._sections.slice(0, index)
-        .concat(this._sections.slice(index + 1, this._sections.length));
+  // TODO(TS): Unclear what is model here, provide a better explanation
+  _handleAddedSectionRemoved(e: CustomEvent & {model: {index: string}}) {
+    if (!this._sections) {
+      return;
+    }
+    const index = Number(e.model.index);
+    if (isNaN(index)) {
+      return;
+    }
+    this._sections = this._sections
+      .slice(0, index)
+      .concat(this._sections.slice(index + 1, this._sections.length));
   }
 
-  _handleEditingChanged(editing, editingOld) {
+  _handleEditingChanged(editing: boolean, editingOld: boolean) {
     // Ignore when editing gets set initially.
-    if (!editingOld || editing) { return; }
+    if (!editingOld || editing) {
+      return;
+    }
     // Remove any unsaved but added refs.
     if (this._sections) {
       this._sections = this._sections.filter(p => !p.value.added);
@@ -283,7 +315,11 @@
     // Restore inheritFrom.
     if (this._inheritsFrom) {
       this._inheritsFrom = {...this._originalInheritsFrom};
-      this._inheritFromFilter = this._inheritsFrom.name;
+      this._inheritFromFilter =
+        'name' in this._inheritsFrom ? this._inheritsFrom.name : undefined;
+    }
+    if (!this._local) {
+      return;
     }
     for (const key of Object.keys(this._local)) {
       if (this._local[key].added) {
@@ -292,18 +328,11 @@
     }
   }
 
-  /**
-   * @param {!Defs.projectAccessInput} addRemoveObj
-   * @param {!Array} path
-   * @param {string} type add or remove
-   * @param {!Object=} opt_value value to add if the type is 'add'
-   * @return {!Defs.projectAccessInput}
-   */
-  _updateAddRemoveObj(addRemoveObj, path, type, opt_value) {
-    let curPos = addRemoveObj[type];
+  _updateRemoveObj(addRemoveObj: {remove: PropertyTreeNode}, path: string[]) {
+    let curPos: PropertyTreeNode = addRemoveObj.remove;
     for (const item of path) {
       if (!curPos[item]) {
-        if (item === path[path.length - 1] && type === 'remove') {
+        if (item === path[path.length - 1]) {
           if (path[path.length - 2] === 'permissions') {
             curPos[item] = {rules: {}};
           } else if (path.length === 1) {
@@ -311,13 +340,36 @@
           } else {
             curPos[item] = {};
           }
-        } else if (item === path[path.length - 1] && type === 'add') {
-          curPos[item] = opt_value;
         } else {
           curPos[item] = {};
         }
       }
-      curPos = curPos[item];
+      // The last item can be a PrimitiveValue, but we don't use it
+      // All intermediate items are PropertyTreeNode
+      // TODO(TS): rewrite this loop and process the last item explicitly
+      curPos = curPos[item] as PropertyTreeNode;
+    }
+    return addRemoveObj;
+  }
+
+  _updateAddObj(
+    addRemoveObj: {add: PropertyTreeNode},
+    path: string[],
+    value: PropertyTreeNode | PrimitiveValue
+  ) {
+    let curPos: PropertyTreeNode = addRemoveObj.add;
+    for (const item of path) {
+      if (!curPos[item]) {
+        if (item === path[path.length - 1]) {
+          curPos[item] = value;
+        } else {
+          curPos[item] = {};
+        }
+      }
+      // The last item can be a PrimitiveValue, but we don't use it
+      // All intermediate items are PropertyTreeNode
+      // TODO(TS): rewrite this loop and process the last item explicitly
+      curPos = curPos[item] as PropertyTreeNode;
     }
     return addRemoveObj;
   }
@@ -325,58 +377,69 @@
   /**
    * Used to recursively remove any objects with a 'deleted' bit.
    */
-  _recursivelyRemoveDeleted(obj) {
+  _recursivelyRemoveDeleted(obj: PropertyTreeNode) {
     for (const k in obj) {
-      if (!obj.hasOwnProperty(k)) { continue; }
-
-      if (typeof obj[k] == 'object') {
-        if (obj[k].deleted) {
+      if (!hasOwnProperty(obj, k)) {
+        continue;
+      }
+      const node = obj[k];
+      if (typeof node === 'object') {
+        if (node.deleted) {
           delete obj[k];
           return;
         }
-        this._recursivelyRemoveDeleted(obj[k]);
+        this._recursivelyRemoveDeleted(node);
       }
     }
   }
 
-  _recursivelyUpdateAddRemoveObj(obj, addRemoveObj, path = []) {
+  _recursivelyUpdateAddRemoveObj(
+    obj: PropertyTreeNode,
+    addRemoveObj: {
+      add: PropertyTreeNode;
+      remove: PropertyTreeNode;
+    },
+    path: string[] = []
+  ) {
     for (const k in obj) {
-      if (!obj.hasOwnProperty(k)) { continue; }
-      if (typeof obj[k] == 'object') {
-        const updatedId = obj[k].updatedId;
+      if (!hasOwnProperty(obj, k)) {
+        continue;
+      }
+      const node = obj[k];
+      if (typeof node === 'object') {
+        const updatedId = node.updatedId;
         const ref = updatedId ? updatedId : k;
-        if (obj[k].deleted) {
-          this._updateAddRemoveObj(addRemoveObj,
-              path.concat(k), 'remove');
+        if (node.deleted) {
+          this._updateRemoveObj(addRemoveObj, path.concat(k));
           continue;
-        } else if (obj[k].modified) {
-          this._updateAddRemoveObj(addRemoveObj,
-              path.concat(k), 'remove');
-          this._updateAddRemoveObj(addRemoveObj, path.concat(ref), 'add',
-              obj[k]);
+        } else if (node.modified) {
+          this._updateRemoveObj(addRemoveObj, path.concat(k));
+          this._updateAddObj(addRemoveObj, path.concat(ref), node);
           /* Special case for ref changes because they need to be added and
            removed in a different way. The new ref needs to include all
            changes but also the initial state. To do this, instead of
            continuing with the same recursion, just remove anything that is
            deleted in the current state. */
           if (updatedId && updatedId !== k) {
-            this._recursivelyRemoveDeleted(addRemoveObj.add[updatedId]);
+            this._recursivelyRemoveDeleted(
+              addRemoveObj.add[updatedId] as PropertyTreeNode
+            );
           }
           continue;
-        } else if (obj[k].added) {
-          this._updateAddRemoveObj(addRemoveObj,
-              path.concat(ref), 'add', obj[k]);
+        } else if (node.added) {
+          this._updateAddObj(addRemoveObj, path.concat(ref), node);
           /**
            * As add / delete both can happen in the new section,
            * so here to make sure it will remove the deleted ones.
            *
            * @see Issue 11339
            */
-          this._recursivelyRemoveDeleted(addRemoveObj.add[k]);
+          this._recursivelyRemoveDeleted(
+            addRemoveObj.add[k] as PropertyTreeNode
+          );
           continue;
         }
-        this._recursivelyUpdateAddRemoveObj(obj[k], addRemoveObj,
-            path.concat(k));
+        this._recursivelyUpdateAddRemoveObj(node, addRemoveObj, path.concat(k));
       }
     }
   }
@@ -384,28 +447,40 @@
   /**
    * Returns an object formatted for saving or submitting access changes for
    * review
-   *
-   * @return {!Defs.projectAccessInput}
    */
   _computeAddAndRemove() {
-    const addRemoveObj = {
+    const addRemoveObj: {
+      add: PropertyTreeNode;
+      remove: PropertyTreeNode;
+      parent?: string | null;
+    } = {
       add: {},
       remove: {},
     };
 
-    const originalInheritsFromId = this._originalInheritsFrom ?
-      singleDecodeURL(this._originalInheritsFrom.id) : null;
-    const inheritsFromId = this._inheritsFrom ?
-      singleDecodeURL(this._inheritsFrom.id) : null;
+    const originalInheritsFromId = this._originalInheritsFrom
+      ? singleDecodeURL(this._originalInheritsFrom.id)
+      : null;
+    // TODO(TS): this._inheritsFrom as ProjectInfo might be a mistake.
+    // _inheritsFrom can be {}
+    const inheritsFromId = this._inheritsFrom
+      ? singleDecodeURL((this._inheritsFrom as ProjectInfo).id)
+      : null;
 
     const inheritFromChanged =
-        // Inherit from changed
-        (originalInheritsFromId &&
-            originalInheritsFromId !== inheritsFromId) ||
-        // Inherit from added (did not have one initially);
-        (!originalInheritsFromId && inheritsFromId);
+      // Inherit from changed
+      (originalInheritsFromId && originalInheritsFromId !== inheritsFromId) ||
+      // Inherit from added (did not have one initially);
+      (!originalInheritsFromId && inheritsFromId);
 
-    this._recursivelyUpdateAddRemoveObj(this._local, addRemoveObj);
+    if (!this._local) {
+      return addRemoveObj;
+    }
+
+    this._recursivelyUpdateAddRemoveObj(
+      (this._local as unknown) as PropertyTreeNode,
+      addRemoveObj
+    );
 
     if (inheritFromChanged) {
       addRemoveObj.parent = inheritsFromId;
@@ -414,6 +489,9 @@
   }
 
   _handleCreateSection() {
+    if (!this._local) {
+      return;
+    }
     let newRef = 'refs/for/*';
     // Avoid using an already used key for the placeholder, since it
     // immediately gets added to an object.
@@ -424,83 +502,105 @@
     this.push('_sections', {id: newRef, value: section});
     this.set(['_local', newRef], section);
     flush();
-    this.root.querySelector('gr-access-section:last-of-type')
-        .editReference();
+    // Template already instantiated at this point
+    (this.root!.querySelector(
+      'gr-access-section:last-of-type'
+    ) as GrAccessSection).editReference();
   }
 
-  _getObjforSave() {
+  _getObjforSave(): ProjectAccessInput | undefined {
     const addRemoveObj = this._computeAddAndRemove();
     // If there are no changes, don't actually save.
-    if (!Object.keys(addRemoveObj.add).length &&
-        !Object.keys(addRemoveObj.remove).length &&
-        !addRemoveObj.parent) {
-      this.dispatchEvent(new CustomEvent('show-alert', {
-        detail: {message: NOTHING_TO_SAVE},
-        bubbles: true,
-        composed: true,
-      }));
+    if (
+      !Object.keys(addRemoveObj.add).length &&
+      !Object.keys(addRemoveObj.remove).length &&
+      !addRemoveObj.parent
+    ) {
+      this.dispatchEvent(
+        new CustomEvent('show-alert', {
+          detail: {message: NOTHING_TO_SAVE},
+          bubbles: true,
+          composed: true,
+        })
+      );
       return;
     }
-    const obj = {
+    const obj: ProjectAccessInput = ({
       add: addRemoveObj.add,
       remove: addRemoveObj.remove,
-    };
+    } as unknown) as ProjectAccessInput;
     if (addRemoveObj.parent) {
       obj.parent = addRemoveObj.parent;
     }
     return obj;
   }
 
-  _handleSave(e) {
+  _handleSave(e: Event) {
     const obj = this._getObjforSave();
-    if (!obj) { return; }
-    const button = e && e.target;
+    if (!obj) {
+      return;
+    }
+    const button = e && (e.target as GrButton);
     if (button) {
       button.loading = true;
     }
-    return this.$.restAPI.setRepoAccessRights(this.repo, obj)
-        .then(() => {
-          this._reload(this.repo);
-        })
-        .finally(() => {
-          this._modified = false;
-          if (button) {
-            button.loading = false;
-          }
-        });
-  }
-
-  _handleSaveForReview(e) {
-    const obj = this._getObjforSave();
-    if (!obj) { return; }
-    const button = e && e.target;
-    if (button) {
-      button.loading = true;
+    const repo = this.repo;
+    if (!repo) {
+      return Promise.resolve();
     }
     return this.$.restAPI
-        .setRepoAccessRightsForReview(this.repo, obj)
-        .then(change => {
-          GerritNav.navigateToChange(change);
-        })
-        .finally(() => {
-          this._modified = false;
-          if (button) {
-            button.loading = false;
-          }
-        });
+      .setRepoAccessRights(repo, obj)
+      .then(() => {
+        this._reload(repo);
+      })
+      .finally(() => {
+        this._modified = false;
+        if (button) {
+          button.loading = false;
+        }
+      });
   }
 
-  _computeSaveReviewBtnClass(canUpload) {
+  _handleSaveForReview(e: Event) {
+    const obj = this._getObjforSave();
+    if (!obj) {
+      return;
+    }
+    const button = e && (e.target as GrButton);
+    if (button) {
+      button.loading = true;
+    }
+    if (!this.repo) {
+      return;
+    }
+    return this.$.restAPI
+      .setRepoAccessRightsForReview(this.repo, obj)
+      .then(change => {
+        GerritNav.navigateToChange(change);
+      })
+      .finally(() => {
+        this._modified = false;
+        if (button) {
+          button.loading = false;
+        }
+      });
+  }
+
+  _computeSaveReviewBtnClass(canUpload?: boolean) {
     return !canUpload ? 'invisible' : '';
   }
 
-  _computeSaveBtnClass(ownerOf) {
+  _computeSaveBtnClass(ownerOf?: GitRef[]) {
     return ownerOf && ownerOf.length === 0 ? 'invisible' : '';
   }
 
-  _computeMainClass(ownerOf, canUpload, editing) {
+  _computeMainClass(
+    ownerOf: GitRef[] | undefined,
+    canUpload: boolean,
+    editing: boolean
+  ) {
     const classList = [];
-    if (ownerOf && ownerOf.length > 0 || canUpload) {
+    if ((ownerOf && ownerOf.length > 0) || canUpload) {
       classList.push('admin');
     }
     if (editing) {
@@ -509,10 +609,13 @@
     return classList.join(' ');
   }
 
-  _computeParentHref(repoName) {
-    return getBaseUrl() +
-        `/admin/repos/${encodeURL(repoName, true)},access`;
+  _computeParentHref(repoName: RepoName) {
+    return getBaseUrl() + `/admin/repos/${encodeURL(repoName, true)},access`;
   }
 }
 
-customElements.define(GrRepoAccess.is, GrRepoAccess);
+declare global {
+  interface HTMLElementTagNameMap {
+    'gr-repo-access': GrRepoAccess;
+  }
+}