Editing JavaScript/Notes/TypeConversion

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== Types ==
== Types ==
* Number  
Number  
* String  
String  
* Boolean  
Boolean  
* Null
Null
* Undefined
Undefined
* Object  
Object  
There are five primitive types in JavaScript. Everything else is an object.
There are five primitive types in JavaScript. Everything else is an object.


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var t = !""; // true. Empty string is falsy.
var t = !""; // true. Empty string is falsy.
var f = !"f"; // false. Non-empty strings other than "0" are not falsy, here.
var f = !"f"; // false. Non-empty strings are not falsy.
Boolean(""); // false.
Boolean(""); // false.
</source>
</source>
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=== Converting to Number ===
=== Converting to Number ===
Converting strings is a very common requirement and many approaches can be used. Any mathematical operator except the concatenation/addition operator will force type-conversion to number.
Converting strings is a very common requirement and many approaches can be used. Any mathematical operator except the concatenation/addition operator will force type-conversion to number.
<source lang="javascript">
var d1 = new Date(NaN);
var d2 = new Date(NaN);
d1.setFullYear(2000);
d2.setFullYear(2000);
d1 >= d2; // true, conversion to number.
d1 <= d2; // true, conversion to number.
d1 == d2 // false, different objects.
</source>


== parseInt(s, radix) ==
== parseInt(s, radix) ==
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