When a variable is assigned an <code>undefined</code> or <code>null</code> value, it has no properties. Trying to access properties of such a variable anyway results in a <code>TypeError</code>, causing abrupt termination of the script if the error is not caught in a <code>catch</code> block. But instead of <code>catch</code>-ing this condition, it is best to avoid it altogether.

== Noncompliant Code Example

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if (x === undefined) {
  console.log(x.length); // Noncompliant; TypeError will be thrown
}
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include::../see.adoc[]