Move HotbarStore to new format

Signed-off-by: Sebastian Malton <sebastian@malton.name>

packages/core/src/common/base-store/base-store.ts

@@ -35,7 +35,7 @@ export interface BaseStoreParams<T> extends Omit<ConfOptions<T>, "migrations"> {
    *
    * @param data the parsed information read from the stored JSON file
    */
-  fromStore(data: T): void;
+  fromStore(data: Partial<T>): void;
 
   /**
    * toJSON is called when syncing the store to the filesystem. It should

packages/core/src/common/catalog/helpers.ts

@@ -0,0 +1,83 @@
+/**
+ * Copyright (c) OpenLens Authors. All rights reserved.
+ * Licensed under MIT License. See LICENSE in root directory for more information.
+ */
+
+import type { CatalogEntity } from "./catalog-entity";
+import GraphemeSplitter from "grapheme-splitter";
+import { hasOwnProperty, hasTypedProperty, isObject, isString, iter } from "@k8slens/utilities";
+
+function getNameParts(name: string): string[] {
+  const byWhitespace = name.split(/\s+/);
+
+  if (byWhitespace.length > 1) {
+    return byWhitespace;
+  }
+
+  const byDashes = name.split(/[-_]+/);
+
+  if (byDashes.length > 1) {
+    return byDashes;
+  }
+
+  return name.split(/@+/);
+}
+
+export function limitGraphemeLengthOf(src: string, count: number): string {
+  const splitter = new GraphemeSplitter();
+
+  return iter
+    .chain(splitter.iterateGraphemes(src))
+    .take(count)
+    .join("");
+}
+
+export function computeDefaultShortName(name: string) {
+  if (!name || typeof name !== "string") {
+    return "??";
+  }
+
+  const [rawFirst, rawSecond, rawThird] = getNameParts(name);
+  const splitter = new GraphemeSplitter();
+  const first = splitter.iterateGraphemes(rawFirst);
+  const second = rawSecond ? splitter.iterateGraphemes(rawSecond): first;
+  const third = rawThird ? splitter.iterateGraphemes(rawThird) : iter.newEmpty<string>();
+
+  return iter.chain(iter.take(first, 1))
+    .concat(iter.take(second, 1))
+    .concat(iter.take(third, 1))
+    .join("");
+}
+
+export function getShortName(entity: CatalogEntity): string {
+  return entity.metadata.shortName || computeDefaultShortName(entity.getName());
+}
+
+export function getIconColourHash(entity: CatalogEntity): string {
+  return `${entity.metadata.name}-${entity.metadata.source}`;
+}
+
+export function getIconBackground(entity: CatalogEntity): string | undefined {
+  if (isObject(entity.spec.icon)) {
+    if (hasTypedProperty(entity.spec.icon, "background", isString)) {
+      return entity.spec.icon.background;
+    }
+
+    return hasOwnProperty(entity.spec.icon, "src")
+      ? "transparent"
+      : undefined;
+  }
+
+  return undefined;
+}
+
+export function getIconMaterial(entity: CatalogEntity): string | undefined {
+  if (
+    isObject(entity.spec.icon)
+    && hasTypedProperty(entity.spec.icon, "material", isString)
+  ) {
+    return entity.spec.icon.material;
+  }
+
+  return undefined;
+}

packages/core/src/common/hotbars/store.injectable.ts

@@ -6,16 +6,10 @@ import { getInjectable } from "@ogre-tools/injectable";
 import catalogCatalogEntityInjectable from "../catalog-entities/general-catalog-entities/implementations/catalog-catalog-entity.injectable";
 import { HotbarStore } from "./store";
 import loggerInjectable from "../logger.injectable";
-import directoryForUserDataInjectable from "../app-paths/directory-for-user-data/directory-for-user-data.injectable";
-import getConfigurationFileModelInjectable from "../get-configuration-file-model/get-configuration-file-model.injectable";
-import storeMigrationVersionInjectable from "../vars/store-migration-version.injectable";
 import storeMigrationsInjectable from "../base-store/migrations.injectable";
 import { hotbarStoreMigrationInjectionToken } from "./migrations-token";
-import getBasenameOfPathInjectable from "../path/get-basename.injectable";
+import createBaseStoreInjectable from "../base-store/create-base-store.injectable";
-import { baseStoreIpcChannelPrefixesInjectionToken } from "../base-store/channel-prefix";
+import storeMigrationVersionInjectable from "../vars/store-migration-version.injectable";
-import { persistStateToConfigInjectionToken } from "../base-store/save-to-file";
-import { enlistMessageChannelListenerInjectionToken } from "@k8slens/messaging";
-import { shouldBaseStoreDisableSyncInIpcListenerInjectionToken } from "../base-store/disable-sync";
 
 const hotbarStoreInjectable = getInjectable({
   id: "hotbar-store",
@@ -23,15 +17,9 @@ const hotbarStoreInjectable = getInjectable({
   instantiate: (di) => new HotbarStore({
     catalogCatalogEntity: di.inject(catalogCatalogEntityInjectable),
     logger: di.inject(loggerInjectable),
-    directoryForUserData: di.inject(directoryForUserDataInjectable),
-    getConfigurationFileModel: di.inject(getConfigurationFileModelInjectable),
     storeMigrationVersion: di.inject(storeMigrationVersionInjectable),
     migrations: di.inject(storeMigrationsInjectable, hotbarStoreMigrationInjectionToken),
-    getBasenameOfPath: di.inject(getBasenameOfPathInjectable),
+    createBaseStore: di.inject(createBaseStoreInjectable),
-    ipcChannelPrefixes: di.inject(baseStoreIpcChannelPrefixesInjectionToken),
-    persistStateToConfig: di.inject(persistStateToConfigInjectionToken),
-    enlistMessageChannelListener: di.inject(enlistMessageChannelListenerInjectionToken),
-    shouldDisableSyncInListener: di.inject(shouldBaseStoreDisableSyncInIpcListenerInjectionToken),
   }),
 });
 

packages/core/src/common/hotbars/store.ts

@@ -3,10 +3,9 @@
  * Licensed under MIT License. See LICENSE in root directory for more information.
  */
 
-import { action, comparer, observable, makeObservable, computed } from "mobx";
+import type { IObservableValue } from "mobx";
-import type { BaseStoreDependencies } from "../base-store/base-store";
+import { runInAction, action, comparer, observable } from "mobx";
-import { BaseStore } from "../base-store/base-store";
+import type { BaseStore } from "../base-store/base-store";
-import { toJS } from "../utils";
 import type { CatalogEntity } from "../catalog";
 import { broadcastMessage } from "../ipc";
 import type { Hotbar, CreateHotbarData, CreateHotbarOptions } from "./types";
@@ -15,34 +14,89 @@ import { hotbarTooManyItemsChannel } from "../ipc/hotbar";
 import type { GeneralEntity } from "../catalog-entities";
 import type { Logger } from "../logger";
 import assert from "assert";
+import { getShortName } from "../catalog/helpers";
+import type { Migrations } from "conf/dist/source/types";
+import type { CreateBaseStore } from "../base-store/create-base-store.injectable";
 
 export interface HotbarStoreModel {
   hotbars: Hotbar[];
   activeHotbarId: string;
 }
 
-interface Dependencies extends BaseStoreDependencies {
+interface Dependencies {
   readonly catalogCatalogEntity: GeneralEntity;
   readonly logger: Logger;
+  readonly storeMigrationVersion: string;
+  readonly migrations: Migrations<Record<string, unknown>>;
+  createBaseStore: CreateBaseStore;
 }
 
-export class HotbarStore extends BaseStore<HotbarStoreModel> {
+export class HotbarStore {
-  @observable hotbars: Hotbar[] = [];
+  private readonly store: BaseStore<HotbarStoreModel>;
-  @observable private _activeHotbarId!: string;
+
+  readonly hotbars = observable.array<Hotbar>();
+
+  readonly activeHotbarId = observable.box() as IObservableValue<string>;
 
   constructor(protected readonly dependencies: Dependencies) {
-    super(dependencies, {
+    this.store = this.dependencies.createBaseStore({
       configName: "lens-hotbar-store",
       accessPropertiesByDotNotation: false, // To make dots safe in cluster context names
       syncOptions: {
         equals: comparer.structural,
       },
+      projectVersion: this.dependencies.storeMigrationVersion,
+      migrations: this.dependencies.migrations,
+      fromStore: action((data) => {
+        if (!data.hotbars || !data.hotbars.length) {
+          const hotbar = getEmptyHotbar("Default");
+          const {
+            metadata: {
+              uid,
+              name,
+              source,
+            },
+          } = this.dependencies.catalogCatalogEntity;
+
+          hotbar.items[0] = {
+            entity: {
+              uid,
+              name,
+              source,
+            },
+          };
+          this.hotbars.replace([hotbar]);
+        } else {
+          this.hotbars.replace(data.hotbars);
+        }
+
+        for (const hotbar of this.hotbars) {
+          ensureExactHotbarItemLength(hotbar);
+        }
+
+        if (data.activeHotbarId) {
+          this.activeHotbarId.set(data.activeHotbarId);
+        }
+
+        if (!this.activeHotbarId.get()) {
+          this.activeHotbarId.set(this.hotbars[0].id);
+        }
+
+        const activeHotbarExists = this.hotbars.findIndex(hotbar => hotbar.id === this.activeHotbarId.get()) >= 0;
+
+        if (!activeHotbarExists) {
+          this.activeHotbarId.set(this.hotbars[0].id);
+        }
+      }),
+      toJSON: () => ({
+        hotbars: this.hotbars.toJSON(),
+        activeHotbarId: this.activeHotbarId.get(),
+      }),
     });
-    makeObservable(this);
   }
 
-  @computed get activeHotbarId() {
+  load() {
-    return this._activeHotbarId;
+    this.store.load();
   }
 
   /**
@@ -50,69 +104,29 @@ export class HotbarStore extends BaseStore<HotbarStoreModel> {
    * @param hotbar The hotbar instance, or the index, or its ID
    */
   setActiveHotbar(hotbar: Hotbar | number | string) {
-    if (typeof hotbar === "number") {
+    runInAction(() => {
-      if (hotbar >= 0 && hotbar < this.hotbars.length) {
+      if (typeof hotbar === "number") {
-        this._activeHotbarId = this.hotbars[hotbar].id;
+        if (hotbar >= 0 && hotbar < this.hotbars.length) {
+          this.activeHotbarId.set(this.hotbars[hotbar].id);
+        }
+      } else if (typeof hotbar === "string") {
+        if (this.findById(hotbar)) {
+          this.activeHotbarId.set(hotbar);
+        }
+      } else {
+        if (this.hotbars.indexOf(hotbar) >= 0) {
+          this.activeHotbarId.set(hotbar.id);
+        }
       }
-    } else if (typeof hotbar === "string") {
-      if (this.findById(hotbar)) {
-        this._activeHotbarId = hotbar;
-      }
-    } else {
-      if (this.hotbars.indexOf(hotbar) >= 0) {
-        this._activeHotbarId = hotbar.id;
-      }
-    }
-  }
-
-  private hotbarIndexById(id: string) {
-    return this.hotbars.findIndex((hotbar) => hotbar.id === id);
-  }
-
-  private hotbarIndex(hotbar: Hotbar) {
-    return this.hotbars.indexOf(hotbar);
-  }
-
-  @computed get activeHotbarIndex() {
-    return this.hotbarIndexById(this.activeHotbarId);
-  }
-
-  @action
-  protected fromStore(data: Partial<HotbarStoreModel> = {}) {
-    if (!data.hotbars || !data.hotbars.length) {
-      const hotbar = getEmptyHotbar("Default");
-      const {
-        metadata: { uid, name, source },
-      } = this.dependencies.catalogCatalogEntity;
-      const initialItem = { entity: { uid, name, source }};
-
-      hotbar.items[0] = initialItem;
-
-      this.hotbars = [hotbar];
-    } else {
-      this.hotbars = data.hotbars;
-    }
-
-    this.hotbars.forEach(ensureExactHotbarItemLength);
-
-    if (data.activeHotbarId) {
-      this._activeHotbarId = data.activeHotbarId;
-    }
-
-    if (!this._activeHotbarId) {
-      this._activeHotbarId = this.hotbars[0].id;
-    }
-  }
-
-  toJSON(): HotbarStoreModel {
-    return toJS({
-      hotbars: this.hotbars,
-      activeHotbarId: this.activeHotbarId,
     });
   }
 
+  private getActiveHotbarIndex() {
+    return this.hotbars.findIndex((hotbar) => hotbar.id === this.activeHotbarId.get());
+  }
+
   getActive(): Hotbar {
-    const hotbar = this.findById(this.activeHotbarId);
+    const hotbar = this.findById(this.activeHotbarId.get());
 
     assert(hotbar, "There MUST always be an active hotbar");
 
@@ -127,96 +141,108 @@ export class HotbarStore extends BaseStore<HotbarStoreModel> {
     return this.hotbars.find((hotbar) => hotbar.id === id);
   }
 
-  @action
   add(data: CreateHotbarData, { setActive = false }: CreateHotbarOptions = {}) {
-    const hotbar = getEmptyHotbar(data.name, data.id);
+    runInAction(() => {
+      const hotbar = getEmptyHotbar(data.name, data.id);
 
-    this.hotbars.push(hotbar);
+      this.hotbars.push(hotbar);
 
-    if (setActive) {
+      if (setActive) {
-      this._activeHotbarId = hotbar.id;
+        this.activeHotbarId.set(hotbar.id);
-    }
-  }
-
-  @action
-  setHotbarName(id: string, name: string): void {
-    const index = this.hotbars.findIndex((hotbar) => hotbar.id === id);
-
-    if (index < 0) {
-      return this.dependencies.logger.warn(
-        `[HOTBAR-STORE]: cannot setHotbarName: unknown id`,
-        { id },
-      );
-    }
-
-    this.hotbars[index].name = name;
-  }
-
-  @action
-  remove(hotbar: Hotbar) {
-    assert(this.hotbars.length >= 2, "Cannot remove the last hotbar");
-
-    this.hotbars = this.hotbars.filter((h) => h !== hotbar);
-
-    if (this.activeHotbarId === hotbar.id) {
-      this.setActiveHotbar(0);
-    }
-  }
-
-  @action
-  addToHotbar(item: CatalogEntity, cellIndex?: number) {
-    const hotbar = this.getActive();
-    const uid = item.getId();
-    const name = item.getName();
-
-    if (typeof uid !== "string") {
-      throw new TypeError("CatalogEntity's ID must be a string");
-    }
-
-    if (typeof name !== "string") {
-      throw new TypeError("CatalogEntity's NAME must be a string");
-    }
-
-    if (this.isAddedToActive(item)) {
-      return;
-    }
-
-    const entity = {
-      uid,
-      name,
-      source: item.metadata.source,
-    };
-    const newItem = { entity };
-
-    if (cellIndex === undefined) {
-      // Add item to empty cell
-      const emptyCellIndex = hotbar.items.indexOf(null);
-
-      if (emptyCellIndex != -1) {
-        hotbar.items[emptyCellIndex] = newItem;
-      } else {
-        broadcastMessage(hotbarTooManyItemsChannel);
       }
-    } else if (0 <= cellIndex && cellIndex < hotbar.items.length) {
+    });
-      hotbar.items[cellIndex] = newItem;
+  }
-    } else {
+
-      this.dependencies.logger.error(
+  setHotbarName(id: string, name: string): void {
-        `[HOTBAR-STORE]: cannot pin entity to hotbar outside of index range`,
+    runInAction(() => {
-        { entityId: uid, hotbarId: hotbar.id, cellIndex },
+      const index = this.hotbars.findIndex((hotbar) => hotbar.id === id);
-      );
+
-    }
+      if (index < 0) {
+        return this.dependencies.logger.warn(
+          `[HOTBAR-STORE]: cannot setHotbarName: unknown id`,
+          { id },
+        );
+      }
+
+      this.hotbars[index].name = name;
+    });
+  }
+
+  remove(hotbar: Hotbar) {
+    runInAction(() => {
+      assert(this.hotbars.length >= 2, "Cannot remove the last hotbar");
+
+      this.hotbars.replace(this.hotbars.filter((h) => h.id !== hotbar.id));
+
+      if (this.activeHotbarId.get() === hotbar.id) {
+        this.activeHotbarId.set(this.hotbars[0].id);
+      }
+    });
+  }
+
+  addToHotbar(item: CatalogEntity, cellIndex?: number) {
+    runInAction(() => {
+
+      const hotbar = this.getActive();
+      const uid = item.getId();
+      const name = item.getName();
+      const shortName = getShortName(item);
+
+      if (typeof uid !== "string") {
+        throw new TypeError("CatalogEntity's ID must be a string");
+      }
+
+      if (typeof name !== "string") {
+        throw new TypeError("CatalogEntity's NAME must be a string");
+      }
+
+      if (typeof shortName !== "string") {
+        throw new TypeError("CatalogEntity's SHORT_NAME must be a string");
+      }
+
+      if (this.isAddedToActive(item)) {
+        return;
+      }
+
+      const entity = {
+        uid,
+        name,
+        source: item.metadata.source,
+        shortName,
+      };
+      const newItem = { entity };
+
+      if (cellIndex === undefined) {
+        // Add item to empty cell
+        const emptyCellIndex = hotbar.items.indexOf(null);
+
+        if (emptyCellIndex != -1) {
+          hotbar.items[emptyCellIndex] = newItem;
+        } else {
+          broadcastMessage(hotbarTooManyItemsChannel);
+        }
+      } else if (0 <= cellIndex && cellIndex < hotbar.items.length) {
+        hotbar.items[cellIndex] = newItem;
+      } else {
+        this.dependencies.logger.error(
+          `[HOTBAR-STORE]: cannot pin entity to hotbar outside of index range`,
+          { entityId: uid, hotbarId: hotbar.id, cellIndex },
+        );
+      }
+    });
   }
 
-  @action
   removeFromHotbar(uid: string): void {
-    const hotbar = this.getActive();
+    runInAction(() => {
-    const index = hotbar.items.findIndex((item) => item?.entity.uid === uid);
+      const hotbar = this.getActive();
+      const index = hotbar.items.findIndex((item) => item?.entity.uid === uid);
 
-    if (index < 0) {
+      if (index < 0) {
-      return;
+        return;
-    }
+      }
 
-    hotbar.items[index] = null;
+      hotbar.items[index] = null;
+    });
   }
 
   /**
@@ -224,18 +250,19 @@ export class HotbarStore extends BaseStore<HotbarStoreModel> {
    * @param uid The `EntityId` that each hotbar item refers to
    * @returns A function that will (in an action) undo the removing of the hotbar items. This function will not complete if the hotbar has changed.
    */
-  @action
   removeAllHotbarItems(uid: string) {
-    for (const hotbar of this.hotbars) {
+    runInAction(() => {
-      const index = hotbar.items.findIndex((i) => i?.entity.uid === uid);
+      for (const hotbar of this.hotbars) {
+        const index = hotbar.items.findIndex((i) => i?.entity.uid === uid);
 
-      if (index >= 0) {
+        if (index >= 0) {
-        hotbar.items[index] = null;
+          hotbar.items[index] = null;
+        }
       }
-    }
+    });
   }
 
-  findClosestEmptyIndex(from: number, direction = 1) {
+  private findClosestEmptyIndex(from: number, direction = 1) {
     let index = from;
     const hotbar = this.getActive();
 
@@ -246,56 +273,61 @@ export class HotbarStore extends BaseStore<HotbarStoreModel> {
     return index;
   }
 
-  @action
   restackItems(from: number, to: number): void {
-    const { items } = this.getActive();
+    runInAction(() => {
-    const source = items[from];
+      const { items } = this.getActive();
-    const moveDown = from < to;
+      const source = items[from];
+      const moveDown = from < to;
 
-    if (
+      if (
-      from < 0 ||
+        from < 0 ||
-      to < 0 ||
+        to < 0 ||
-      from >= items.length ||
+        from >= items.length ||
-      to >= items.length ||
+        to >= items.length ||
-      isNaN(from) ||
+        isNaN(from) ||
-      isNaN(to)
+        isNaN(to)
-    ) {
+      ) {
-      throw new Error("Invalid 'from' or 'to' arguments");
+        throw new Error("Invalid 'from' or 'to' arguments");
-    }
+      }
 
-    if (from == to) {
+      if (from == to) {
-      return;
+        return;
-    }
+      }
 
-    items.splice(from, 1, null);
+      items.splice(from, 1, null);
 
-    if (items[to] == null) {
+      if (items[to] == null) {
-      items.splice(to, 1, source);
+        items.splice(to, 1, source);
-    } else {
+      } else {
-      // Move cells up or down to closes empty cell
+        // Move cells up or down to closes empty cell
-      items.splice(this.findClosestEmptyIndex(to, moveDown ? -1 : 1), 1);
+        items.splice(this.findClosestEmptyIndex(to, moveDown ? -1 : 1), 1);
-      items.splice(to, 0, source);
+        items.splice(to, 0, source);
-    }
+      }
+    });
   }
 
   switchToPrevious() {
-    let index = this.activeHotbarIndex - 1;
+    runInAction(() => {
+      let index = this.getActiveHotbarIndex() - 1;
 
-    if (index < 0) {
+      if (index < 0) {
-      index = this.hotbars.length - 1;
+        index = this.hotbars.length - 1;
-    }
+      }
 
-    this.setActiveHotbar(index);
+      this.setActiveHotbar(index);
+    });
   }
 
   switchToNext() {
-    let index = this.activeHotbarIndex + 1;
+    runInAction(() => {
+      let index = this.getActiveHotbarIndex() + 1;
 
-    if (index >= this.hotbars.length) {
+      if (index >= this.hotbars.length) {
-      index = 0;
+        index = 0;
-    }
+      }
 
-    this.setActiveHotbar(index);
+      this.setActiveHotbar(index);
+    });
   }
 
   /**
@@ -316,7 +348,7 @@ export class HotbarStore extends BaseStore<HotbarStoreModel> {
   }
 
   getDisplayIndex(hotbar: Hotbar): string {
-    const index = this.hotbarIndex(hotbar);
+    const index = this.hotbars.indexOf(hotbar);
 
     if (index < 0) {
       return "??";

packages/core/src/renderer/components/avatar/avatar.tsx

@@ -8,9 +8,9 @@ import styles from "./avatar.module.scss";
 import type { ImgHTMLAttributes, MouseEventHandler } from "react";
 import React from "react";
 import randomColor from "randomcolor";
-import GraphemeSplitter from "grapheme-splitter";
 import type { SingleOrMany } from "@k8slens/utilities";
-import { cssNames, isDefined, iter } from "@k8slens/utilities";
+import { cssNames } from "@k8slens/utilities";
+import { computeDefaultShortName } from "../../../common/catalog/helpers";
 
 export interface AvatarProps {
   title: string;
@@ -28,40 +28,6 @@ export interface AvatarProps {
   "data-testid"?: string;
 }
 
-function getNameParts(name: string): string[] {
-  const byWhitespace = name.split(/\s+/);
-
-  if (byWhitespace.length > 1) {
-    return byWhitespace;
-  }
-
-  const byDashes = name.split(/[-_]+/);
-
-  if (byDashes.length > 1) {
-    return byDashes;
-  }
-
-  return name.split(/@+/);
-}
-
-function getLabelFromTitle(title: string) {
-  if (!title) {
-    return "??";
-  }
-
-  const [rawFirst, rawSecond, rawThird] = getNameParts(title);
-  const splitter = new GraphemeSplitter();
-  const first = splitter.iterateGraphemes(rawFirst);
-  const second = rawSecond ? splitter.iterateGraphemes(rawSecond): first;
-  const third = rawThird ? splitter.iterateGraphemes(rawThird) : iter.newEmpty();
-
-  return [
-    ...iter.take(first, 1),
-    ...iter.take(second, 1),
-    ...iter.take(third, 1),
-  ].filter(isDefined).join("");
-}
-
 export const Avatar = ({
   title,
   variant = "rounded",
@@ -104,6 +70,6 @@ export const Avatar = ({
           alt={title}
         />
       )
-      : children || getLabelFromTitle(title)}
+      : children || computeDefaultShortName(title)}
   </div>
 );

packages/core/src/renderer/components/hotbar/hotbar-selector.tsx

@@ -59,7 +59,7 @@ const NonInjectedHotbarSelector = observer(({ hotbar, hotbarStore, openCommandOv
     <div className={styles.HotbarSelector}>
       <Icon
         material="arrow_left"
-        className={cssNames(styles.Icon, styles.previous)}
+        className={cssNames(styles.Icon)}
         onClick={onPrevClick}/>
       <div className={styles.HotbarIndex}>
         <Badge

packages/utility-features/utilities/src/iter.ts

@@ -14,6 +14,7 @@ interface Iterator<T> extends Iterable<T> {
   flatMap<U>(fn: (val: T) => U[]): Iterator<U>;
   concat(src2: IterableIterator<T>): Iterator<T>;
   join(sep?: string): string;
+  take(count: number): Iterator<T>;
 }
 
 function chain<T>(src: IterableIterator<T>): Iterator<T> {
@@ -26,6 +27,7 @@ function chain<T>(src: IterableIterator<T>): Iterator<T> {
     join: (sep) => join(src, sep),
     collect: (fn) => fn(src),
     concat: (src2) => chain(concat(src, src2)),
+    take: (count) => chain(take(src, count)),
     [Symbol.iterator]: () => src,
   };
 }