Switch to a discriminated unions

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/editor/autocomplete.ts

@@ -17,13 +17,13 @@ limitations under the License.
 
 import {KeyboardEvent} from "react";
 
-import {BasePart, CommandPartCreator, PartCreator} from "./parts";
+import {Part, CommandPartCreator, PartCreator} from "./parts";
 import DocumentPosition from "./position";
 import {ICompletion} from "../autocomplete/Autocompleter";
 import Autocomplete from "../components/views/rooms/Autocomplete";
 
 export interface ICallback {
-    replaceParts?: BasePart[];
+    replaceParts?: Part[];
     close?: boolean;
 }
 
@@ -32,7 +32,7 @@ export type GetAutocompleterComponent = () => Autocomplete;
 export type UpdateQuery = (test: string) => Promise<void>;
 
 export default class AutocompleteWrapperModel {
-    private queryPart: BasePart;
+    private queryPart: Part;
     private partIndex: number;
 
     constructor(
@@ -89,7 +89,7 @@ export default class AutocompleteWrapperModel {
         this.getAutocompleterComponent().moveSelection(+1);
     }
 
-    onPartUpdate(part: BasePart, pos: DocumentPosition) {
+    onPartUpdate(part: Part, pos: DocumentPosition) {
         // cache the typed value and caret here
         // so we can restore it in onComponentSelectionChange when the value is undefined (meaning it should be the typed text)
         this.queryPart = part;

src/editor/caret.ts

@@ -19,7 +19,7 @@ import {needsCaretNodeBefore, needsCaretNodeAfter} from "./render";
 import Range from "./range";
 import EditorModel from "./model";
 import DocumentPosition, {IPosition} from "./position";
-import {BasePart} from "./parts";
+import {Part} from "./parts";
 
 export type Caret = Range | DocumentPosition;
 
@@ -104,7 +104,7 @@ export function getLineAndNodePosition(model: EditorModel, caretPosition: IPosit
     return {lineIndex, nodeIndex, offset};
 }
 
-function findNodeInLineForPart(parts: BasePart[], partIndex: number) {
+function findNodeInLineForPart(parts: Part[], partIndex: number) {
     let lineIndex = 0;
     let nodeIndex = -1;
 
@@ -140,7 +140,7 @@ function findNodeInLineForPart(parts: BasePart[], partIndex: number) {
     return {lineIndex, nodeIndex};
 }
 
-function moveOutOfUneditablePart(parts: BasePart[], partIndex: number, nodeIndex: number, offset: number) {
+function moveOutOfUneditablePart(parts: Part[], partIndex: number, nodeIndex: number, offset: number) {
     // move caret before or after uneditable part
     const part = parts[partIndex];
     if (part && !part.canEdit) {

src/editor/history.ts

@@ -16,12 +16,11 @@ limitations under the License.
 
 import EditorModel from "./model";
 import {IDiff} from "./diff";
-import {ISerializedPart} from "./parts";
+import {SerializedPart} from "./parts";
-import Range from "./range";
 import {Caret} from "./caret";
 
 interface IHistory {
-    parts: ISerializedPart[];
+    parts: SerializedPart[];
     caret: Caret;
 }
 

src/editor/model.ts

@@ -18,7 +18,7 @@ limitations under the License.
 import {diffAtCaret, diffDeletion, IDiff} from "./diff";
 import DocumentPosition, {IPosition} from "./position";
 import Range from "./range";
-import {BasePart, ISerializedPart, PartCreator} from "./parts";
+import {SerializedPart, Part, PartCreator} from "./parts";
 import AutocompleteWrapperModel, {ICallback} from "./autocomplete";
 import DocumentOffset from "./offset";
 import {Caret} from "./caret";
@@ -49,7 +49,7 @@ type UpdateCallback = (caret: Caret, inputType?: string, diff?: IDiff) => void;
 type ManualTransformCallback = () => Caret;
 
 export default class EditorModel {
-    private _parts: BasePart[];
+    private _parts: Part[];
     private readonly _partCreator: PartCreator;
     private activePartIdx: number = null;
     private _autoComplete: AutocompleteWrapperModel = null;
@@ -57,7 +57,7 @@ export default class EditorModel {
     private autoCompletePartCount = 0;
     private transformCallback: TransformCallback = null;
 
-    constructor(parts: BasePart[], partCreator: PartCreator, private updateCallback: UpdateCallback = null) {
+    constructor(parts: Part[], partCreator: PartCreator, private updateCallback: UpdateCallback = null) {
         this._parts = parts;
         this._partCreator = partCreator;
         this.transformCallback = null;
@@ -94,7 +94,7 @@ export default class EditorModel {
         return new EditorModel(this._parts, this._partCreator, this.updateCallback);
     }
 
-    private insertPart(index: number, part: BasePart) {
+    private insertPart(index: number, part: Part) {
         this._parts.splice(index, 0, part);
         if (this.activePartIdx >= index) {
             ++this.activePartIdx;
@@ -118,7 +118,7 @@ export default class EditorModel {
         }
     }
 
-    private replacePart(index: number, part: BasePart) {
+    private replacePart(index: number, part: Part) {
         this._parts.splice(index, 1, part);
     }
 
@@ -158,7 +158,7 @@ export default class EditorModel {
         }
     }
 
-    reset(serializedParts: ISerializedPart[], caret: Caret, inputType: string) {
+    reset(serializedParts: SerializedPart[], caret: Caret, inputType: string) {
         this._parts = serializedParts.map(p => this._partCreator.deserializePart(p));
         if (!caret) {
             caret = this.getPositionAtEnd();
@@ -180,7 +180,7 @@ export default class EditorModel {
      * @param {DocumentPosition} position the position to start inserting at
      * @return {Number} the amount of characters added
      */
-    insert(parts: BasePart[], position: IPosition) {
+    insert(parts: Part[], position: IPosition) {
         const insertIndex = this.splitAt(position);
         let newTextLength = 0;
         for (let i = 0; i < parts.length; ++i) {
@@ -420,7 +420,7 @@ export default class EditorModel {
         return new Range(this, positionA, positionB);
     }
 
-    replaceRange(startPosition: DocumentPosition, endPosition: DocumentPosition, parts: BasePart[]) {
+    replaceRange(startPosition: DocumentPosition, endPosition: DocumentPosition, parts: Part[]) {
         // convert end position to offset, so it is independent of how the document is split into parts
         // which we'll change when splitting up at the start position
         const endOffset = endPosition.asOffset(this);

src/editor/operations.ts

@@ -15,13 +15,13 @@ limitations under the License.
 */
 
 import Range from "./range";
-import {BasePart} from "./parts";
+import {Part} from "./parts";
 
 /**
  * Some common queries and transformations on the editor model
  */
 
-export function replaceRangeAndExpandSelection(range: Range, newParts: BasePart[]) {
+export function replaceRangeAndExpandSelection(range: Range, newParts: Part[]) {
     const {model} = range;
     model.transform(() => {
         const oldLen = range.length;
@@ -32,7 +32,7 @@ export function replaceRangeAndExpandSelection(range: Range, newParts: BasePart[
     });
 }
 
-export function replaceRangeAndMoveCaret(range: Range, newParts: BasePart[]) {
+export function replaceRangeAndMoveCaret(range: Range, newParts: Part[]) {
     const {model} = range;
     model.transform(() => {
         const oldLen = range.length;

src/editor/parts.ts

@@ -19,15 +19,66 @@ import {MatrixClient} from "matrix-js-sdk/src/client";
 import {RoomMember} from "matrix-js-sdk/src/models/room-member";
 import {Room} from "matrix-js-sdk/src/models/room";
 
-import AutocompleteWrapperModel, {GetAutocompleterComponent, UpdateCallback, UpdateQuery} from "./autocomplete";
+import AutocompleteWrapperModel, {
+    GetAutocompleterComponent,
+    UpdateCallback,
+    UpdateQuery
+} from "./autocomplete";
 import * as Avatar from "../Avatar";
 
-export interface ISerializedPart {
+interface ISerializedPart {
-    type: string;
+    type: Type.Plain | Type.Newline | Type.Command | Type.PillCandidate;
     text: string;
 }
 
-export abstract class BasePart {
+interface ISerializedPillPart {
+    type: Type.AtRoomPill | Type.RoomPill | Type.UserPill;
+    text: string;
+    resourceId: string;
+}
+
+export type SerializedPart = ISerializedPart | ISerializedPillPart;
+
+enum Type {
+    Plain = "plain",
+    Newline = "newline",
+    Command = "command",
+    UserPill = "user-pill",
+    RoomPill = "room-pill",
+    AtRoomPill = "at-room-pill",
+    PillCandidate = "pill-candidate",
+}
+
+interface IBasePart {
+    text: string;
+    type: Type.Plain | Type.Newline;
+    canEdit: boolean;
+
+    createAutoComplete(updateCallback: UpdateCallback): void;
+
+    serialize(): SerializedPart;
+    remove(offset: number, len: number): string;
+    split(offset: number): IBasePart;
+    validateAndInsert(offset: number, str: string, inputType: string): boolean;
+    appendUntilRejected(str: string, inputType: string): string;
+    updateDOMNode(node: Node);
+    canUpdateDOMNode(node: Node);
+    toDOMNode(): Node;
+}
+
+interface IPillCandidatePart extends Omit<IBasePart, "type" | "createAutoComplete"> {
+    type: Type.PillCandidate | Type.Command;
+    createAutoComplete(updateCallback: UpdateCallback): AutocompleteWrapperModel;
+}
+
+interface IPillPart extends Omit<IBasePart, "type" | "resourceId"> {
+    type: Type.AtRoomPill | Type.RoomPill | Type.UserPill;
+    resourceId: string;
+}
+
+export type Part = IBasePart | IPillCandidatePart | IPillPart;
+
+abstract class BasePart {
     protected _text: string;
 
     constructor(text = "") {
@@ -42,7 +93,7 @@ export abstract class BasePart {
         return true;
     }
 
-    merge(part: BasePart) {
+    merge(part: Part) {
         return false;
     }
 
@@ -94,7 +145,7 @@ export abstract class BasePart {
         return true;
     }
 
-    createAutoComplete(updateCallback): AutocompleteWrapperModel | void {}
+    createAutoComplete(updateCallback: UpdateCallback): void {}
 
     trim(len: number) {
         const remaining = this._text.substr(len);
@@ -106,7 +157,7 @@ export abstract class BasePart {
         return this._text;
     }
 
-    abstract get type(): string;
+    abstract get type(): Type;
 
     get canEdit() {
         return true;
@@ -116,8 +167,11 @@ export abstract class BasePart {
         return `${this.type}(${this.text})`;
     }
 
-    serialize(): ISerializedPart {
+    serialize(): SerializedPart {
-        return {type: this.type, text: this.text};
+        return {
+            type: this.type as ISerializedPart["type"],
+            text: this.text,
+        };
     }
 
     abstract updateDOMNode(node: Node);
@@ -125,8 +179,7 @@ export abstract class BasePart {
     abstract toDOMNode(): Node;
 }
 
-// exported for unit tests, should otherwise only be used through PartCreator
+abstract class PlainBasePart extends BasePart {
-export class PlainPart extends BasePart {
     acceptsInsertion(chr: string, offset: number, inputType: string) {
         if (chr === "\n") {
             return false;
@@ -150,10 +203,6 @@ export class PlainPart extends BasePart {
         return false;
     }
 
-    get type() {
-        return "plain";
-    }
-
     updateDOMNode(node: Node) {
         if (node.textContent !== this.text) {
             node.textContent = this.text;
@@ -165,7 +214,14 @@ export class PlainPart extends BasePart {
     }
 }
 
-export abstract class PillPart extends BasePart {
+// exported for unit tests, should otherwise only be used through PartCreator
+export class PlainPart extends PlainBasePart implements IBasePart {
+    get type(): IBasePart["type"] {
+        return Type.Plain;
+    }
+}
+
+abstract class PillPart extends BasePart implements IPillPart {
     constructor(public resourceId: string, label) {
         super(label);
     }
@@ -223,12 +279,14 @@ export abstract class PillPart extends BasePart {
         return false;
     }
 
+    abstract get type(): IPillPart["type"];
+
     abstract get className(): string;
 
     abstract setAvatar(node: HTMLElement): void;
 }
 
-class NewlinePart extends BasePart {
+class NewlinePart extends BasePart implements IBasePart {
     acceptsInsertion(chr: string, offset: number) {
         return offset === 0 && chr === "\n";
     }
@@ -251,8 +309,8 @@ class NewlinePart extends BasePart {
         return node.tagName === "BR";
     }
 
-    get type() {
+    get type(): IBasePart["type"] {
-        return "newline";
+        return Type.Newline;
     }
 
     // this makes the cursor skip this part when it is inserted
@@ -283,8 +341,8 @@ class RoomPillPart extends PillPart {
         this._setAvatarVars(node, avatarUrl, initialLetter);
     }
 
-    get type() {
+    get type(): IPillPart["type"] {
-        return "room-pill";
+        return Type.RoomPill;
     }
 
     get className() {
@@ -293,8 +351,8 @@ class RoomPillPart extends PillPart {
 }
 
 class AtRoomPillPart extends RoomPillPart {
-    get type() {
+    get type(): IPillPart["type"] {
-        return "at-room-pill";
+        return Type.AtRoomPill;
     }
 }
 
@@ -321,28 +379,29 @@ class UserPillPart extends PillPart {
         this._setAvatarVars(node, avatarUrl, initialLetter);
     }
 
-    get type() {
+    get type(): IPillPart["type"] {
-        return "user-pill";
+        return Type.UserPill;
     }
 
     get className() {
         return "mx_UserPill mx_Pill";
     }
 
-    serialize() {
+    serialize(): ISerializedPillPart {
         return {
-            ...super.serialize(),
+            type: this.type,
+            text: this.text,
             resourceId: this.resourceId,
         };
     }
 }
 
-class PillCandidatePart extends PlainPart {
+class PillCandidatePart extends PlainBasePart implements IPillCandidatePart {
     constructor(text: string, private autoCompleteCreator: IAutocompleteCreator) {
         super(text);
     }
 
-    createAutoComplete(updateCallback): AutocompleteWrapperModel {
+    createAutoComplete(updateCallback: UpdateCallback): AutocompleteWrapperModel {
         return this.autoCompleteCreator.create(updateCallback);
     }
 
@@ -362,8 +421,8 @@ class PillCandidatePart extends PlainPart {
         return true;
     }
 
-    get type() {
+    get type(): IPillCandidatePart["type"] {
-        return "pill-candidate";
+        return Type.PillCandidate;
     }
 }
 
@@ -399,7 +458,7 @@ export class PartCreator {
         this.autoCompleteCreator.create = autoCompleteCreator(this);
     }
 
-    createPartForInput(input: string, partIndex: number, inputType?: string): BasePart {
+    createPartForInput(input: string, partIndex: number, inputType?: string): Part {
         switch (input[0]) {
             case "#":
             case "@":
@@ -416,20 +475,20 @@ export class PartCreator {
         return this.plain(text);
     }
 
-    deserializePart(part: ISerializedPart) {
+    deserializePart(part: SerializedPart): Part {
         switch (part.type) {
-            case "plain":
+            case Type.Plain:
                 return this.plain(part.text);
-            case "newline":
+            case Type.Newline:
                 return this.newline();
-            case "at-room-pill":
+            case Type.AtRoomPill:
                 return this.atRoomPill(part.text);
-            case "pill-candidate":
+            case Type.PillCandidate:
                 return this.pillCandidate(part.text);
-            case "room-pill":
+            case Type.RoomPill:
                 return this.roomPill(part.text);
-            case "user-pill":
+            case Type.UserPill:
-                return this.userPill(part.text, (part as PillPart).resourceId);
+                return this.userPill(part.text, part.resourceId);
         }
     }
 
@@ -491,7 +550,7 @@ export class CommandPartCreator extends PartCreator {
         return new CommandPart(text, this.autoCompleteCreator);
     }
 
-    deserializePart(part: BasePart) {
+    deserializePart(part: Part): Part {
         if (part.type === "command") {
             return this.command(part.text);
         } else {
@@ -501,7 +560,7 @@ export class CommandPartCreator extends PartCreator {
 }
 
 class CommandPart extends PillCandidatePart {
-    get type() {
+    get type(): IPillCandidatePart["type"] {
-        return "command";
+        return Type.Command;
     }
 }

src/editor/position.ts

@@ -16,15 +16,15 @@ limitations under the License.
 
 import DocumentOffset from "./offset";
 import EditorModel from "./model";
-import {BasePart} from "./parts";
+import {Part} from "./parts";
 
 export interface IPosition {
     index: number;
     offset: number;
 }
 
-type Callback = (part: BasePart, startIdx: number, endIdx: number) => void;
+type Callback = (part: Part, startIdx: number, endIdx: number) => void;
-type Predicate = (index: number, offset: number, part: BasePart) => boolean;
+type Predicate = (index: number, offset: number, part: Part) => boolean;
 
 export default class DocumentPosition implements IPosition {
     constructor(public readonly index: number, public readonly offset: number) {

src/editor/render.ts

@@ -15,16 +15,15 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import {BasePart} from "./parts";
+import {Part} from "./parts";
 import EditorModel from "./model";
-import {instanceOf} from "prop-types";
 
-export function needsCaretNodeBefore(part: BasePart, prevPart: BasePart) {
+export function needsCaretNodeBefore(part: Part, prevPart: Part) {
     const isFirst = !prevPart || prevPart.type === "newline";
     return !part.canEdit && (isFirst || !prevPart.canEdit);
 }
 
-export function needsCaretNodeAfter(part: BasePart, isLastOfLine: boolean) {
+export function needsCaretNodeAfter(part: Part, isLastOfLine: boolean) {
     return !part.canEdit && isLastOfLine;
 }
 
@@ -83,7 +82,7 @@ function removeChildren(parent: HTMLElement) {
     }
 }
 
-function reconcileLine(lineContainer: ChildNode, parts: BasePart[]) {
+function reconcileLine(lineContainer: ChildNode, parts: Part[]) {
     let currentNode;
     let prevPart;
     const lastPart = parts[parts.length - 1];

src/editor/serialize.ts

@@ -18,7 +18,6 @@ limitations under the License.
 import Markdown from '../Markdown';
 import {makeGenericPermalink} from "../utils/permalinks/Permalinks";
 import EditorModel from "./model";
-import {PillPart} from "./parts";
 
 export function mdSerialize(model: EditorModel) {
     return model.parts.reduce((html, part) => {
@@ -32,7 +31,7 @@ export function mdSerialize(model: EditorModel) {
                 return html + part.text;
             case "room-pill":
             case "user-pill":
-                return html + `[${part.text.replace(/[[\\\]]/g, c => "\\" + c)}](${makeGenericPermalink((part as PillPart).resourceId)})`;
+                return html + `[${part.text.replace(/[[\\\]]/g, c => "\\" + c)}](${makeGenericPermalink(part.resourceId)})`;
         }
     }, "");
 }