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snippets/js/s/is-readable-stream.md

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+---
+title: Stream is readable
+type: snippet
+language: javascript
+tags: [node,type]
+cover: working-bee
+dateModified: 2020-10-20T23:02:01+03:00
+---
+
+Checks if the given argument is a readable stream.
+
+- Check if the value is different from `null`.
+- Use `typeof` to check if the value is of type `object` and the `pipe` property is of type `function`.
+- Additionally check if the `typeof` the `_read` and `_readableState` properties are `function` and `object` respectively.
+
+```js
+const isReadableStream = val =>
+  val !== null &&
+  typeof val === 'object' &&
+  typeof val.pipe === 'function' &&
+  typeof val._read === 'function' &&
+  typeof val._readableState === 'object';
+```
+
+```js
+const fs = require('fs');
+
+isReadableStream(fs.createReadStream('test.txt')); // true
+```