null in javascript code example
Example 1: javascript not null
if (variable !== null) {
console.log("Var is NOT null");
}
Example 2: javascript null or object
What it is What output shows you
when you write |console.log(typeof(variable);
Undefined: "undefined"
Null: "object"
Boolean: "boolean"
Number: "number"
String: "string"
Function object: "function"
E4X XML object: "xml"
E4X XMLList object: "xml"
NodeList "Nodelist [more data]"
HTMLCollection "HTMLCollection(1) [more data]"
Example 3: javascript check for null variables
var myVar=null;
if(myVar === null){
}
if (typeof myVar === 'undefined'){
}
Example 4: javascript null check
if (Var === null) {
}
Example 5: data types in javascript
1, 1.0
'String', "String"
true, false
{id: 1;}
[1, 2, 3]
Example 6: js null is object typeof
In the first implementation of JavaScript, JavaScript values were represented
as a type tag and a value. The type tag for objects was 0. null was represented
as the NULL pointer (0x00 in most platforms). Consequently, null had 0 as type
tag, hence the "object" typeof return value. (reference)
A fix was proposed for ECMAScript (via an opt-in), but was rejected.
It would have resulted in typeof null === 'null'.