# Introduction In this lab, we will explore how to check if a given argument is a writable stream in JavaScript. We will use a function that checks if the value is different from `null`, if it has a `pipe` property of type `function`, and if it also has `_write` and `_writableState` properties of type `function` and `object` respectively. Through this lab, we will gain a better understanding of how to work with streams in JavaScript.
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