Can a null value automatically occur in JS

Question

In JS an "undefined" value could occur automatically by mistake.(eg:- if you call a function which does not return any thing)

Can a "null" value occur automatically?

Undefined does not occur because of a mistake, it is a designed feature. null cannot occur automatically (whatever automatically. means). You may be given null as a return value from an API, but it is neither automatic nor accidental. — Randy Casburn
– Randy Casburn, Commented Nov 2, 2020 at 20:41
Calling a function that doesn't exist throws a ReferenceError — chazsolo
– chazsolo, Commented Nov 2, 2020 at 20:41

jfriend00 · Accepted Answer · 2020-11-02 22:16:52Z

2

undefined is what is returned when you attempt to access a property that is not there or an array value that is not there. It is also the initial value of a variable that has been declared, but not assigned a value yet. These are not really mistakes, but the way the language is designed when you request a value that is not there.

null does not occur by default like undefined does. If a variable or property or return value is null, that is because some programmer or API specifically assigned or returned null.

Also, calling a function that does not exist throws a ReferenceError.

answered Nov 2, 2020 at 22:16

jfriend00

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