Method _emitStateChange

packages/muya/src/state/index.ts:149–182

()

    }

    private _emitStateChange() {
        if (this._isGoing)
            return;

        this._isGoing = true;

        requestAnimationFrame(() => {
            // Wrap compose in a lambda — `Array.prototype.reduce` passes
            // (acc, current, index, array) to the callback, but
            // `json1.type.compose` only accepts (op1, op2). Without the
            // wrapper TS rejects the signature mismatch.
            // `compose` returns JSONOp (= null | JSONOpList); when the cache
            // contains at least one op the result is the composed list,
            // never null. The reduce above runs only when _operationCache is
            // non-empty (guarded by the requestAnimationFrame in
            // `_emitStateChange`), and a non-empty cache always composes to
            // a non-null op.
            const op = this._operationCache.reduce(
                (acc, curr) => json1.type.compose(acc, curr) as JSONOpList,
            );
            const prevDoc = this.getState();
            this.apply(op);
            // TODO: remove doc in future
            const doc = this.getState();
            this.muya.eventCenter.emit('json-change', {
                op,
                source: 'user',
                prevDoc,
                doc,
            });
            this._operationCache = [];
            this._isGoing = false;
        });
    }
}

export default JSONState;