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Anjana Vakil
Engineer & Educator | Observable Ambassador | Karaoke Enthusiast
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Functional JavaScript First Steps
By
Anjana Vakil
Edited
Dec 4, 2020
42 forks
39 stars
Functional JavaScript First Steps
Functional JavaScript First Steps
What is functional programming?
Exercise: Pure Functions
Staying out of the loop with recursion
Exercise: Iteration vs. Recursion
Flying first class with higher-order functions
Exercise: Filter, Map, Reduce
Getting closure
Exercise: Closures & Currying
It's functions all the way down
Exercise: Function Composition
Immutability
Exercise: Avoiding mutation
Recap & takeaways
Next steps
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function
getDate
(
)
{
return
new
Date
(
)
.
toDateString
(
)
;
}
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function
getWorkshopDate
(
)
{
return
new
Date
(
2020
,
11
,
4
)
.
toDateString
(
)
;
}
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function
toHex
(
n
)
{
let
hex
=
n
.
toString
(
16
)
;
return
hex
.
padStart
(
2
,
'0'
)
;
}
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function
rgbToHex
(
R
,
G
,
B
)
{
return
'#'
+
[
toHex
(
R
)
,
toHex
(
G
)
,
toHex
(
B
)
]
.
join
(
''
)
;
}
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function
setColor
(
R
,
G
,
B
)
{
const
hex
=
rgbToHex
(
R
,
G
,
B
)
;
const
colorMe
=
document
.
getElementById
(
'color-me'
)
;
colorMe
.
setAttribute
(
'style'
,
'color: '
+
hex
)
;
}
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async
function
readJsonFile
(
filename
)
{
const
file
=
await
fetch
(
'https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_hour.geojson'
)
;
return
await
file
.
json
(
)
;
}
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function
writeJsonString
(
object
)
{
return
JSON
.
stringify
(
object
,
null
,
2
)
;
}
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function
exclusiveOr
(
A
,
B
)
{
return
(
A
||
B
)
&&
!
(
A
&&
B
)
;
}
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function
computeTruthTable
(
operator
)
{
const
truthValues
=
[
true
,
false
]
;
const
table
=
[
]
;
for
(
const
A
of
truthValues
)
{
for
(
const
B
of
truthValues
)
{
const
value
=
operator
(
A
,
B
)
;
table
.
push
(
{
A
,
B
,
value
}
)
;
}
}
return
table
;
}
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function
showTruthTable
(
operator
)
{
console
.
table
(
computeTruthTable
(
operator
)
)
;
}
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setColor
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setColorAnswer
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exclusiveOr
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showTruthTable
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evaluate
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