json-joy
Version:
Collection of libraries for building collaborative editing apps.
43 lines (42 loc) • 1.79 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.placeCursor = void 0;
const constants_1 = require("../../../../json-crdt-extensions/peritext/rga/constants");
const json_crdt_patch_1 = require("../../../../json-crdt-patch");
/**
* Given an undo/redo patch/batch, calculates a good cursor position to place
* the cursor after the patch is applied, so that the user can continue typing
* from the same logical position.
*
* @param patch Undo/Redo patch
* @returns Range
*/
const placeCursor = (txt, batch) => {
const batchLength = batch.length;
for (let j = batchLength - 1; j >= 0; j--) {
const patch = batch[j];
const ops = patch.ops;
const length = ops.length;
for (let i = length - 1; i >= 0; i--) {
const op = ops[i];
if (op instanceof json_crdt_patch_1.InsStrOp || op instanceof json_crdt_patch_1.InsBinOp || op instanceof json_crdt_patch_1.InsArrOp) {
const opId = op.id;
const lastCharId = new json_crdt_patch_1.Timestamp(opId.sid, opId.time + op.span() - 1);
const point = txt.point(lastCharId, constants_1.Anchor.After);
const cursor = txt.range(point);
return cursor;
}
else if (op instanceof json_crdt_patch_1.DelOp && (0, json_crdt_patch_1.equal)(op.obj, txt.str.id)) {
const lastSpan = op.what[op.what.length - 1];
if (lastSpan) {
const point = txt.point(lastSpan, constants_1.Anchor.Before);
point.halfstep(-1);
const cursor = txt.range(point);
return cursor;
}
}
}
}
return;
};
exports.placeCursor = placeCursor;