# Global objects
<!--introduced_in=v0.10.0-->
<!-- type=misc -->
These objects are available in all modules. The following variables may appear
to be global but are not. They exist only in the scope of modules, see the
[module system documentation][]:
* [`__dirname`][]
* [`__filename`][]
* [`exports`][]
* [`module`][]
* [`require()`][]
The objects listed here are specific to Node.js. There are [built-in objects][]
that are part of the JavaScript language itself, which are also globally
accessible.
## Class: `AbortController`
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added:
- v15.0.0
- v14.17.0
changes:
- version: v15.4.0
pr-url: https://github.com/nodejs/node/pull/35949
description: No longer experimental.
-->
<!-- type=global -->
A utility class used to signal cancelation in selected `Promise`-based APIs.
The API is based on the Web API [`AbortController`][].
```js
const ac = new AbortController();
ac.signal.addEventListener('abort', () => console.log('Aborted!'),
{ once: true });
ac.abort();
console.log(ac.signal.aborted); // Prints true
```
### `abortController.abort([reason])`
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- v14.17.0
changes:
- version:
- v17.2.0
- v16.14.0
pr-url: https://github.com/nodejs/node/pull/40807
description: Added the new optional reason argument.
-->
* `reason` {any} An optional reason, retrievable on the `AbortSignal`'s
`reason` property.
Triggers the abort signal, causing the `abortController.signal` to emit
the `'abort'` event.
### `abortController.signal`
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* Type: {AbortSignal}
### Class: `AbortSignal`
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* Extends: {EventTarget}
The `AbortSignal` is used to notify observers when the
`abortController.abort()` method is called.
#### Static method: `AbortSignal.abort([reason])`
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added:
- v15.12.0
- v14.17.0
changes:
- version:
- v17.2.0
- v16.14.0
pr-url: https://github.com/nodejs/node/pull/40807
description: Added the new optional reason argument.
-->
* `reason`: {any}
* Returns: {AbortSignal}
Returns a new already aborted `AbortSignal`.
#### Static method: `AbortSignal.timeout(delay)`
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- v16.14.0
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* `delay` {number} The number of milliseconds to wait before triggering
the AbortSignal.
Returns a new `AbortSignal` which will be aborted in `delay` milliseconds.
#### Static method: `AbortSignal.any(signals)`
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* `signals` {AbortSignal\[]} The `AbortSignal`s of which to compose a new `AbortSignal`.
Returns a new `AbortSignal` which will be aborted if any of the provided
signals are aborted. Its [`abortSignal.reason`][] will be set to whichever
one of the `signals` caused it to be aborted.
#### Event: `'abort'`
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The `'abort'` event is emitted when the `abortController.abort()` method
is called. The callback is invoked with a single object argument with a
single `type` property set to `'abort'`:
```js
const ac = new AbortController();
// Use either the onabort property...
ac.signal.onabort = () => console.log('aborted!');
// Or the EventTarget API...
ac.signal.addEventListener('abort', (event) => {
console.log(event.type); // Prints 'abort'
}, { once: true });
ac.abort();
```
The `AbortController` with which the `AbortSignal` is associated will only
ever trigger the `'abort'` event once. We recommended that code check
that the `abortSignal.aborted` attribute is `false` before adding an `'abort'`
event listener.
Any event listeners attached to the `AbortSignal` should use the
`{ once: true }` option (or, if using the `EventEmitter` APIs to attach a
listener, use the `once()` method) to ensure that the event listener is
removed as soon as the `'abort'` event is handled. Failure to do so may
result in memory leaks.
#### `abortSignal.aborted`
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* Type: {boolean} True after the `AbortController` has been aborted.
#### `abortSignal.onabort`
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- v15.0.0
- v14.17.0
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* Type: {Function}
An optional callback function that may be set by user code to be notified
when the `abortController.abort()` function has been called.
#### `abortSignal.reason`
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added:
- v17.2.0
- v16.14.0
-->
* Type: {any}
An optional reason specified when the `AbortSignal` was triggered.
```js
const ac = new AbortController();
ac.abort(new Error('boom!'));
console.log(ac.signal.reason); // Error: boom!
```
#### `abortSignal.throwIfAborted()`
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added: v17.3.0
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If `abortSignal.aborted` is `true`, throws `abortSignal.reason`.
## Class: `Blob`
<!-- YAML
added: v18.0.0
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<!-- type=global -->
See {Blob}.
## Class: `Buffer`
<!-- YAML
added: v0.1.103
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<!-- type=global -->
* {Function}
Used to handle binary data. See the [buffer section][].
## Class: `ByteLengthQueuingStrategy`
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added: v18.0.0
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> Stability: 1 - Experimental.
A browser-compatible implementation of [`ByteLengthQueuingStrategy`][].
## `__dirname`
This variable may appear to be global but is not. See [`__dirname`][].
## `__filename`
This variable may appear to be global but is not. See [`__filename`][].
## `atob(data)`
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added: v16.0.0
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> Stability: 3 - Legacy. Use `Buffer.from(data, 'base64')` instead.
Global alias for [`buffer.atob()`][].
## `BroadcastChannel`
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added: v18.0.0
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See {BroadcastChannel}.
## `btoa(data)`
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added: v16.0.0
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> Stability: 3 - Legacy. Use `buf.toString('base64')` instead.
Global alias for [`buffer.btoa()`][].
## `clearImmediate(immediateObject)`
<!-- YAML
added: v0.9.1
-->
<!--type=global-->
[`clearImmediate`][] is described in the [timers][] section.
## `clearInterval(intervalObject)`
<!-- YAML
added: v0.0.1
-->
<!--type=global-->
[`clearInterval`][] is described in the [timers][] section.
## `clearTimeout(timeoutObject)`
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added: v0.0.1
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<!--type=global-->
[`clearTimeout`][] is described in the [timers][] section.
## Class: `CompressionStream`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`CompressionStream`][].
## `console`
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added: v0.1.100
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<!-- type=global -->
* {Object}
Used to print to stdout and stderr. See the [`console`][] section.
## Class: `CountQueuingStrategy`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`CountQueuingStrategy`][].
## `Crypto`
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added: v17.6.0
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> Stability: 1 - Experimental. Enable this API with the
> [`--experimental-global-webcrypto`][] CLI flag.
A browser-compatible implementation of {Crypto}. This global is available
only if the Node.js binary was compiled with including support for the
`node:crypto` module.
## `crypto`
<!-- YAML
added: v17.6.0
-->
> Stability: 1 - Experimental. Enable this API with the
> [`--experimental-global-webcrypto`][] CLI flag.
A browser-compatible implementation of the [Web Crypto API][].
## `CryptoKey`
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added: v17.6.0
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> Stability: 1 - Experimental. Enable this API with the
> [`--experimental-global-webcrypto`][] CLI flag.
A browser-compatible implementation of {CryptoKey}. This global is available
only if the Node.js binary was compiled with including support for the
`node:crypto` module.
## `CustomEvent`
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added: v18.7.0
-->
> Stability: 1 - Experimental. Enable this API with the
> [`--experimental-global-customevent`][] CLI flag.
<!-- type=global -->
A browser-compatible implementation of the [`CustomEvent` Web API][].
## Class: `DecompressionStream`
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added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`DecompressionStream`][].
## `Event`
<!-- YAML
added: v15.0.0
changes:
- version: v15.4.0
pr-url: https://github.com/nodejs/node/pull/35949
description: No longer experimental.
-->
<!-- type=global -->
A browser-compatible implementation of the `Event` class. See
[`EventTarget` and `Event` API][] for more details.
## `EventTarget`
<!-- YAML
added: v15.0.0
changes:
- version: v15.4.0
pr-url: https://github.com/nodejs/node/pull/35949
description: No longer experimental.
-->
<!-- type=global -->
A browser-compatible implementation of the `EventTarget` class. See
[`EventTarget` and `Event` API][] for more details.
## `exports`
This variable may appear to be global but is not. See [`exports`][].
## `fetch`
<!-- YAML
added: v17.5.0
changes:
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-global-fetch` CLI flag.
-->
> Stability: 1 - Experimental. Disable this API with the [`--no-experimental-fetch`][]
> CLI flag.
A browser-compatible implementation of the [`fetch()`][] function.
## Class `FormData`
<!-- YAML
added: v17.6.0
changes:
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-global-fetch` CLI flag.
-->
> Stability: 1 - Experimental. Disable this API with the [`--no-experimental-fetch`][]
> CLI flag.
A browser-compatible implementation of {FormData}.
## `global`
<!-- YAML
added: v0.1.27
-->
<!-- type=global -->
> Stability: 3 - Legacy. Use [`globalThis`][] instead.
* {Object} The global namespace object.
In browsers, the top-level scope has traditionally been the global scope. This
means that `var something` will define a new global variable, except within
ECMAScript modules. In Node.js, this is different. The top-level scope is not
the global scope; `var something` inside a Node.js module will be local to that
module, regardless of whether it is a [CommonJS module][] or an
[ECMAScript module][].
## Class `Headers`
<!-- YAML
added: v17.5.0
changes:
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-global-fetch` CLI flag.
-->
> Stability: 1 - Experimental. Disable this API with the [`--no-experimental-fetch`][]
> CLI flag.
A browser-compatible implementation of {Headers}.
## `MessageChannel`
<!-- YAML
added: v15.0.0
-->
<!-- type=global -->
The `MessageChannel` class. See [`MessageChannel`][] for more details.
## `MessageEvent`
<!-- YAML
added: v15.0.0
-->
<!-- type=global -->
The `MessageEvent` class. See [`MessageEvent`][] for more details.
## `MessagePort`
<!-- YAML
added: v15.0.0
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<!-- type=global -->
The `MessagePort` class. See [`MessagePort`][] for more details.
## `module`
This variable may appear to be global but is not. See [`module`][].
## `performance`
<!-- YAML
added: v16.0.0
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The [`perf_hooks.performance`][] object.
## `process`
<!-- YAML
added: v0.1.7
-->
<!-- type=global -->
* {Object}
The process object. See the [`process` object][] section.
## `queueMicrotask(callback)`
<!-- YAML
added: v11.0.0
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<!-- type=global -->
* `callback` {Function} Function to be queued.
The `queueMicrotask()` method queues a microtask to invoke `callback`. If
`callback` throws an exception, the [`process` object][] `'uncaughtException'`
event will be emitted.
The microtask queue is managed by V8 and may be used in a similar manner to
the [`process.nextTick()`][] queue, which is managed by Node.js. The
`process.nextTick()` queue is always processed before the microtask queue
within each turn of the Node.js event loop.
```js
// Here, `queueMicrotask()` is used to ensure the 'load' event is always
// emitted asynchronously, and therefore consistently. Using
// `process.nextTick()` here would result in the 'load' event always emitting
// before any other promise jobs.
DataHandler.prototype.load = async function load(key) {
const hit = this._cache.get(key);
if (hit !== undefined) {
queueMicrotask(() => {
this.emit('load', hit);
});
return;
}
const data = await fetchData(key);
this._cache.set(key, data);
this.emit('load', data);
};
```
## Class: `ReadableByteStreamController`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`ReadableByteStreamController`][].
## Class: `ReadableStream`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`ReadableStream`][].
## Class: `ReadableStreamBYOBReader`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`ReadableStreamBYOBReader`][].
## Class: `ReadableStreamBYOBRequest`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`ReadableStreamBYOBRequest`][].
## Class: `ReadableStreamDefaultController`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`ReadableStreamDefaultController`][].
## Class: `ReadableStreamDefaultReader`
<!-- YAML
added: v18.0.0
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> Stability: 1 - Experimental.
A browser-compatible implementation of [`ReadableStreamDefaultReader`][].
## `require()`
This variable may appear to be global but is not. See [`require()`][].
## `Response`
<!-- YAML
added: v17.5.0
changes:
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-global-fetch` CLI flag.
-->
> Stability: 1 - Experimental. Disable this API with the [`--no-experimental-fetch`][]
> CLI flag.
A browser-compatible implementation of {Response}.
## `Request`
<!-- YAML
added: v17.5.0
changes:
- version: v18.0.0
pr-url: https://github.com/nodejs/node/pull/41811
description: No longer behind `--experimental-global-fetch` CLI flag.
-->
> Stability: 1 - Experimental. Disable this API with the [`--no-experimental-fetch`][]
> CLI flag.
A browser-compatible implementation of {Request}.
## `setImmediate(callback[, ...args])`
<!-- YAML
added: v0.9.1
-->
<!-- type=global -->
[`setImmediate`][] is described in the [timers][] section.
## `setInterval(callback, delay[, ...args])`
<!-- YAML
added: v0.0.1
-->
<!-- type=global -->
[`setInterval`][] is described in the [timers][] section.
## `setTimeout(callback, delay[, ...args])`
<!-- YAML
added: v0.0.1
-->
<!-- type=global -->
[`setTimeout`][] is described in the [timers][] section.
## `structuredClone(value[, options])`
<!-- YAML
added: v17.0.0
-->
<!-- type=global -->
The WHATWG [`structuredClone`][] method.
## `SubtleCrypto`
<!-- YAML
added: v17.6.0
-->
> Stability: 1 - Experimental. Enable this API with the
> [`--experimental-global-webcrypto`][] CLI flag.
A browser-compatible implementation of {SubtleCrypto}. This global is available
only if the Node.js binary was compiled with including support for the
`node:crypto` module.
## `DOMException`
<!-- YAML
added: v17.0.0
-->
<!-- type=global -->
The WHATWG `DOMException` class. See [`DOMException`][] for more details.
## `TextDecoder`
<!-- YAML
added: v11.0.0
-->
<!-- type=global -->
The WHATWG `TextDecoder` class. See the [`TextDecoder`][] section.
## Class: `TextDecoderStream`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`TextDecoderStream`][].
## `TextEncoder`
<!-- YAML
added: v11.0.0
-->
<!-- type=global -->
The WHATWG `TextEncoder` class. See the [`TextEncoder`][] section.
## Class: `TextEncoderStream`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`TextEncoderStream`][].
## Class: `TransformStream`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`TransformStream`][].
## Class: `TransformStreamDefaultController`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`TransformStreamDefaultController`][].
## `URL`
<!-- YAML
added: v10.0.0
-->
<!-- type=global -->
The WHATWG `URL` class. See the [`URL`][] section.
## `URLSearchParams`
<!-- YAML
added: v10.0.0
-->
<!-- type=global -->
The WHATWG `URLSearchParams` class. See the [`URLSearchParams`][] section.
## `WebAssembly`
<!-- YAML
added: v8.0.0
-->
<!-- type=global -->
* {Object}
The object that acts as the namespace for all W3C
[WebAssembly][webassembly-org] related functionality. See the
[Mozilla Developer Network][webassembly-mdn] for usage and compatibility.
## Class: `WritableStream`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`WritableStream`][].
## Class: `WritableStreamDefaultController`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`WritableStreamDefaultController`][].
## Class: `WritableStreamDefaultWriter`
<!-- YAML
added: v18.0.0
-->
> Stability: 1 - Experimental.
A browser-compatible implementation of [`WritableStreamDefaultWriter`][].
[CommonJS module]: modules.md
[ECMAScript module]: esm.md
[Web Crypto API]: webcrypto.md
[`--experimental-global-customevent`]: cli.md#--experimental-global-customevent
[`--experimental-global-webcrypto`]: cli.md#--experimental-global-webcrypto
[`--no-experimental-fetch`]: cli.md#--no-experimental-fetch
[`AbortController`]: https://developer.mozilla.org/en-US/docs/Web/API/AbortController
[`ByteLengthQueuingStrategy`]: webstreams.md#class-bytelengthqueuingstrategy
[`CompressionStream`]: webstreams.md#class-compressionstream
[`CountQueuingStrategy`]: webstreams.md#class-countqueuingstrategy
[`CustomEvent` Web API]: https://dom.spec.whatwg.org/#customevent
[`DOMException`]: https://developer.mozilla.org/en-US/docs/Web/API/DOMException
[`DecompressionStream`]: webstreams.md#class-decompressionstream
[`EventTarget` and `Event` API]: events.md#eventtarget-and-event-api
[`MessageChannel`]: worker_threads.md#class-messagechannel
[`MessageEvent`]: https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent/MessageEvent
[`MessagePort`]: worker_threads.md#class-messageport
[`ReadableByteStreamController`]: webstreams.md#class-readablebytestreamcontroller
[`ReadableStreamBYOBReader`]: webstreams.md#class-readablestreambyobreader
[`ReadableStreamBYOBRequest`]: webstreams.md#class-readablestreambyobrequest
[`ReadableStreamDefaultController`]: webstreams.md#class-readablestreamdefaultcontroller
[`ReadableStreamDefaultReader`]: webstreams.md#class-readablestreamdefaultreader
[`ReadableStream`]: webstreams.md#class-readablestream
[`TextDecoderStream`]: webstreams.md#class-textdecoderstream
[`TextDecoder`]: util.md#class-utiltextdecoder
[`TextEncoderStream`]: webstreams.md#class-textencoderstream
[`TextEncoder`]: util.md#class-utiltextencoder
[`TransformStreamDefaultController`]: webstreams.md#class-transformstreamdefaultcontroller
[`TransformStream`]: webstreams.md#class-transformstream
[`URLSearchParams`]: url.md#class-urlsearchparams
[`URL`]: url.md#class-url
[`WritableStreamDefaultController`]: webstreams.md#class-writablestreamdefaultcontroller
[`WritableStreamDefaultWriter`]: webstreams.md#class-writablestreamdefaultwriter
[`WritableStream`]: webstreams.md#class-writablestream
[`__dirname`]: modules.md#__dirname
[`__filename`]: modules.md#__filename
[`abortSignal.reason`]: #abortsignalreason
[`buffer.atob()`]: buffer.md#bufferatobdata
[`buffer.btoa()`]: buffer.md#bufferbtoadata
[`clearImmediate`]: timers.md#clearimmediateimmediate
[`clearInterval`]: timers.md#clearintervaltimeout
[`clearTimeout`]: timers.md#cleartimeouttimeout
[`console`]: console.md
[`exports`]: modules.md#exports
[`fetch()`]: https://developer.mozilla.org/en-US/docs/Web/API/fetch
[`globalThis`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis
[`module`]: modules.md#module
[`perf_hooks.performance`]: perf_hooks.md#perf_hooksperformance
[`process.nextTick()`]: process.md#processnexttickcallback-args
[`process` object]: process.md#process
[`require()`]: modules.md#requireid
[`setImmediate`]: timers.md#setimmediatecallback-args
[`setInterval`]: timers.md#setintervalcallback-delay-args
[`setTimeout`]: timers.md#settimeoutcallback-delay-args
[`structuredClone`]: https://developer.mozilla.org/en-US/docs/Web/API/structuredClone
[buffer section]: buffer.md
[built-in objects]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects
[module system documentation]: modules.md
[timers]: timers.md
[webassembly-mdn]: https://developer.mozilla.org/en-US/docs/WebAssembly
[webassembly-org]: https://webassembly.org
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