monaco-editor
Version:
A browser based code editor
62 lines (59 loc) • 2.38 kB
JavaScript
import { cancelOnDispose } from '../../cancellation.js';
import '../../arrays.js';
import '../../event.js';
import { DisposableStore } from '../../lifecycle.js';
import { autorunWithStoreHandleChanges } from '../reactions/autorun.js';
/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
function runOnChange(observable, cb) {
let _previousValue;
let _firstRun = true;
return autorunWithStoreHandleChanges({
changeTracker: {
createChangeSummary: () => ({ deltas: [], didChange: false }),
handleChange: (context, changeSummary) => {
if (context.didChange(observable)) {
const e = context.change;
if (e !== undefined) {
changeSummary.deltas.push(e);
}
changeSummary.didChange = true;
}
return true;
},
}
}, (reader, changeSummary) => {
const value = observable.read(reader);
const previousValue = _previousValue;
if (changeSummary.didChange) {
_previousValue = value;
// didChange can never be true on the first autorun, so we know previousValue is defined
cb(value, previousValue, changeSummary.deltas);
}
if (_firstRun) {
_firstRun = false;
_previousValue = value;
}
});
}
function runOnChangeWithStore(observable, cb) {
const store = new DisposableStore();
const disposable = runOnChange(observable, (value, previousValue, deltas) => {
store.clear();
cb(value, previousValue, deltas, store);
});
return {
dispose() {
disposable.dispose();
store.dispose();
}
};
}
function runOnChangeWithCancellationToken(observable, cb) {
return runOnChangeWithStore(observable, (value, previousValue, deltas, store) => {
cb(value, previousValue, deltas, cancelOnDispose(store));
});
}
export { runOnChange, runOnChangeWithCancellationToken, runOnChangeWithStore };