Why the Sum of Null and zero is zero

Asked Nov 10 '16 at 15:49

Active Nov 10 '16 at 15:52

Viewed 86 times

We all know the difference between null and zero.

ZERO
"Zero" is a value. It is the unique, known quantity of zero, which is meaningful in arithmetic and other math.

Null
"Null" is a non-value. It is a "placeholder" for a data value that is not known or not specified. mathematical operations cannot be performed on null.

Then how it is possible that

[1, null+null] ---> [1,0]
[1, null+1] ---> [1,1]

So here null undertaking zero as the default value and doing arithmetic operations.Is there any reason behind this operation.

edited Nov 10 '16 at 15:51

asked Nov 10 '16 at 15:49

htoniv

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`null` *is* a value. When converted to a number, it is converted to `0`: `Number(null)`. – Felix Kling Nov 10 '16 at 15:51
`null` in JavaScript is not like the term that is used in other contexts, such as in databases. – trincot Nov 10 '16 at 15:52
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`null + null = 0` implicit coercion to 0 on null values – MX D Nov 10 '16 at 15:53
On a similar topic: http://stackoverflow.com/questions/9032856/what-is-the-explanation-for-these-bizarre-javascript-behaviours-mentioned-in-the/9033306#9033306 – epascarello Nov 10 '16 at 15:53
It's curious inddeed that ToNumber(null) is +0 but ToNumber(undefined) is NaN – Oriol Nov 10 '16 at 15:56

Why the Sum of Null and zero is zero

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