1.8 KiB
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Converting types
As you now know, the number 42
is different than the string '42'
, but if we
write `${42}`
we converted the number to a string !
We see it because of the delimiters, but it is also true for the memory in your computer.
For example we can not multiply strings, if you try to do 'hello' * 2
or
'hello' * 'hello'
you will have an unexpected result.
Well what were you expecting really ?
'hellohello'
maybe ?
So sometimes it is usefull to go from strings to number to boolean and back !
Number
is a function to convert to a number.Boolean
is a function to convert to a boolean.String
is a function to convert to, you guessed it, a string.
So to convert a boolean
to a string
we would write:
String(true)
One other way we can use placeholders
for, is to convert from any values to a
string, but using functions is more clear than abusing placeholder syntax:
let str42Placeholder = `${42}` // was this a mistake ?
let str42Function = String(42) // ah okey we want a string !
so there you have it, calling, arguments and return values, let's see you apply all of that now
Instructions
For this exercise, we provide 3 variables num
, bool
and str
of a matching
type.
Using the magical power of functions, execute the following conversions:
- a
stringFromNumber
variable of the converted value ofnum
to astring
- a
stringFromBoolean
variable of the converted value ofbool
to astring
- a
numberFromString
variable of the converted value ofstr
to anumber
- a
numberFromBoolean
variable of the converted value ofbool
to anumber
- a
booleanFromString
variable of the converted value ofstr
to aboolean
- a
booleanFromNumber
variable of the converted value ofnum
to aboolean