feat(json-crdt-extensions): 🎸 add initial Inline class implementation

Author: streamich

src/json-crdt-extensions/peritext/block/Inline.ts

@@ -0,0 +1,124 @@
+import {printTree} from 'tree-dump/lib/printTree';
+import {OverlayPoint} from '../overlay/OverlayPoint';
+import {stringify} from '../../../json-text/stringify';
+import {SliceBehavior} from '../slice/constants';
+import {Range} from '../rga/Range';
+import type {AbstractRga} from '../../../json-crdt/nodes/rga';
+import type {ChunkSlice} from '../util/ChunkSlice';
+import type {Printable} from 'tree-dump/lib/types';
+import type {PathStep} from '../../../json-pointer';
+import type {Slice} from '../slice/types';
+
+export type Marks = Record<string | number, unknown>;
+
+export class Inline extends Range implements Printable {
+  constructor(
+    rga: AbstractRga<string>,
+    public start: OverlayPoint,
+    public end: OverlayPoint,
+    
+    /**
+     * @todo PERF: for performance reasons, we should consider not passing in
+     * this array. Maybe pass in just the initial chunk and the offset. However,
+     * maybe even the just is not necessary, as the `.start` point should have
+     * its chunk cached, or will have it cached after the first access.
+     */
+    public readonly texts: ChunkSlice[],
+  ) {
+    super(rga, start, end);
+  }
+
+  /**
+   * @returns A stable unique identifier of this *inline* within a list of other
+   *     inlines of the parent block. Can be used for UI libraries to track the
+   *     identity of the inline across renders.
+   */
+  public key(): number | string {
+    const start = this.start;
+    const startId = this.start.id;
+    const endId = this.end.id;
+    const key = startId.sid.toString(36) + start.anchor + startId.time.toString(36) + endId.time.toString(36);
+    return key;
+  }
+
+  public str(): string {
+    let str = '';
+    for (const slice of this.texts) str += slice.view();
+    return str;
+  }
+
+  public marks(): Marks {
+    const marks: Marks = {};
+    const point = this.start as OverlayPoint;
+    const slices: Slice[] = this.texts.length ? point.layers : point.markers;
+    const length = slices.length;
+    for (let i = 0; i < length; i++) {
+      const slice = slices[i];
+      const type = slice.type as PathStep;
+      switch (slice.behavior) {
+        case SliceBehavior.Stack: {
+          let dataList: unknown[] = (marks[type] as unknown[]) || (marks[type] = []);
+          if (!Array.isArray(dataList)) dataList = marks[type] = [dataList];
+          let data = slice.data();
+          if (data === undefined) data = 1;
+          dataList.push(data);
+          break;
+        }
+        case SliceBehavior.Overwrite: {
+          let data = slice.data();
+          if (data === undefined) data = 1;
+          marks[type] = data;
+          break;
+        }
+        case SliceBehavior.Erase: {
+          delete marks[type];
+          break;
+        }
+      }
+    }
+    return marks;
+  }
+
+  public pos(): number {
+    const chunkSlice = this.texts[0];
+    if (!chunkSlice) return -1;
+    const chunk = chunkSlice.chunk;
+    const pos = this.rga.pos(chunk);
+    return pos + chunkSlice.off;
+  }
+
+  // ---------------------------------------------------------------- Printable
+
+  public toString(tab: string = ''): string {
+    const str = this.str();
+    const truncate = str.length > 32;
+    const text = JSON.stringify(truncate ? str.slice(0, 32) : str) + (truncate ? ' …' : '');
+    const startFormatted = this.start.toString(tab, true);
+    const range =
+      this.start.cmp(this.end) === 0 ? startFormatted : `${startFormatted} ↔ ${this.end.toString(tab, true)}`;
+    const header = `${this.constructor.name} ${range} ${text}`;
+    const marks = this.marks();
+    const markKeys = Object.keys(marks);
+    return (
+      header +
+      printTree(tab, [
+        !marks
+          ? null
+          : (tab) =>
+              'attributes' +
+              printTree(
+                tab,
+                markKeys.map((key) => () => key + ' = ' + stringify(marks[key])),
+              ),
+        !this.texts.length
+          ? null
+          : (tab) =>
+              'texts' +
+              printTree(
+                tab,
+                this.texts.map((text) => (tab) => text.toString(tab)),
+              ),
+      ])
+    );
+  }
+}