JavaScript では、変数にどんなデータが入っているかを「実行時」に調べたい場面があります。 そんなときに使えるのが typeof 演算子 です。 typeof は JavaScript で値の「データ型（型）」を調べる演算子 です。

In JavaScript, there are times when you want to check what kind of data is stored in a variable at "runtime". The typeof operator can be used for such cases. typeof is an operator in JavaScript used ...

typeof is an operator that is used to identify the type of any object in javascript. It returns a value that is string. So you can compare any string value from returned value of typeof. // Examples ...

You can use typeof to check the data structure, or type, of a variable. This is useful in debugging when working with multiple data types. If you think you're adding two numbers, but one is actually a ...

sinon.match.typeOf(type) 是 Sinon.js 匹配器（Matcher）体系中用于按数据类型校验测试参数的 API。当你在 spy/stub 的 calledWith、withArgs 等断言中需要“只要参数是某种类型就算匹配”时，它比逐个枚举具体值更简洁、更稳健。读完本文，你将掌握 typeOf 的完整类型清单、与 ...