function promises.readFile
Usage in Deno
```typescript import { promises } from "node:node__fs.d.ts"; ```
readFile(path: PathLike | FileHandle,): Promise<Buffer>
Asynchronously reads the entire contents of a file.
If no encoding is specified (using `options.encoding`), the data is returned
as a `Buffer` object. Otherwise, the data will be a string.
If `options` is a string, then it specifies the encoding.
When the `path` is a directory, the behavior of `fsPromises.readFile()` is
platform-specific. On macOS, Linux, and Windows, the promise will be rejected
with an error. On FreeBSD, a representation of the directory's contents will be
returned.
An example of reading a `package.json` file located in the same directory of the
running code:
```js
import { readFile } from 'node:fs/promises';
try {
const filePath = new URL('./package.json', import.meta.url);
const contents = await readFile(filePath, { encoding: 'utf8' });
console.log(contents);
} catch (err) {
console.error(err.message);
}
```
It is possible to abort an ongoing `readFile` using an `AbortSignal`. If a
request is aborted the promise returned is rejected with an `AbortError`:
```js
import { readFile } from 'node:fs/promises';
try {
const controller = new AbortController();
const { signal } = controller;
const promise = readFile(fileName, { signal });
// Abort the request before the promise settles.
controller.abort();
await promise;
} catch (err) {
// When a request is aborted - err is an AbortError
console.error(err);
}
```
Aborting an ongoing request does not abort individual operating
system requests but rather the internal buffering `fs.readFile` performs.
Any specified `FileHandle` has to support reading.
path: PathLike | FileHandle
filename or `FileHandle`
Promise<Buffer>
Fulfills with the contents of the file.
readFile(path: PathLike | FileHandle,): Promise<string>
Asynchronously reads the entire contents of a file.
path: PathLike | FileHandle
A path to a file. If a URL is provided, it must use the `file:` protocol.
If a `FileHandle` is provided, the underlying file will _not_ be closed automatically.
Promise<string>
readFile(path: PathLike | FileHandle,options?: ,): Promise<string | Buffer>
Asynchronously reads the entire contents of a file.
path: PathLike | FileHandle
A path to a file. If a URL is provided, it must use the `file:` protocol.
If a `FileHandle` is provided, the underlying file will _not_ be closed automatically.
Promise<string | Buffer>