What is array length in JavaScript?

Summary: in this tutorial, you’ll learn about the JavaScript Array length property and how to handle it correctly. By definition, the length property of an array is an unsigned, 32-bit integer that is always numerically greater than the highest index in the array. The value of the length is 2 32.

What is a length property in JavaScript?

The value of the length property is a non-negative integer with a value less than 2 32. The array object observes the length property, and automatically syncs the length value with the array's content. This means: Setting length to a value smaller than the current length truncates the array — elements beyond the new length are deleted.

What is the length property of an array?

By definition, the length property of an array is an unsigned, 32-bit integer that is always numerically greater than the highest index in the array. The value of the length is 2 32. It means that an array can hold up to 4294967296 (2 32) elements. The length property behaves differently depending on the array types including dense and sparse.

How do I find the length of an array?

testvar is the value of that array index, which is the number 2. Numbers don't have a length property, and you're checking for 2.length which is undefined. If you want the length of the array just check testvar.length Integer has no method length. Try string var testvar= {}; testvar ="2"; alert (testvar .length);