Add isStream

snippets/isStream.md

@@ -0,0 +1,14 @@
+### isStream
+
+Checks if the given argument is a stream.
+
+Check if the value is different from `null`, use `typeof` to check if a value is of type `object` and the `pipe` property is of type `function`.
+
+```js
+const isStream = val => val !== null && typeof val === 'object' && typeof val.pipe === 'function';
+```
+
+```js
+const fs = require('fs');
+isStream(fs.createReadStream('test.txt')); // true
+```

tag_database

@@ -154,6 +154,7 @@ isPrimitive:type,function,array,string,intermediate
 isPromiseLike:type,function,promise,intermediate
 isSameDate:date,utility,beginner
 isSorted:array,intermediate
+isStream:type,stream,intermediate
 isString:type,string,beginner
 isSymbol:type,beginner
 isTravisCI:node,intermediate

test/isStream/isStream.js

@@ -0,0 +1,2 @@
+const isStream = val => val !== null && typeof val === 'object' && typeof val.pipe === 'function';
+module.exports = isStream;

test/isStream/isStream.test.js

@@ -0,0 +1,13 @@
+const expect = require('expect');
+const isStream = require('./isStream.js');
+const fs = require('fs');
+
+test('isStream is a Function', () => {
+  expect(isStream).toBeInstanceOf(Function);
+});
+test('isStream returns true for streams', () => {
+  expect(isStream(fs.createReadStream('isStream.js'))).toBeTruthy();
+});
+test('isStream returns false for non-streams', () => {
+  expect(isStream({})).toBeFalsy();
+});