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Functions

atan2

atan2(x, y)

Returns the inverse tangent of x/y in radians between -pi and pi.

Code example

atan2(3, 2) -> 0.982793723247329

case

case(x, c1, r1, c2, r2, ..., (default))

Compare x to each of c1, c2, etc. and return the matching r1, r2 of the first match. If no entry matches, a final optional expression can be returned as default.

Code examples

case("b", "a", 1, "b", 2, "c", 3, 0) -> 2
case("d", "a", 1, "b", 2, "c", 3, 0) -> 0

ceil

ceil(x)

Returns x rounded up to the nearest integer.

Code example

ceil(16.2) -> 17

chars

chars(x)

Creates an array of characters from a string.

Code example

"test".chars() -> ["t", "e", "s", "t"]

chunk

chunk(x, s)

Converts the list x into several lists of length at most s

Code example

chunk([1, 2, 3, 4, 5, 6, 7], 3) -> [[1, 2, 3], [4, 5, 6], [7]]

concat

concat(x, y, ...)

Concatenate any number of strings.

Code examples

concat("Hello, ", "world!") -> "Hello, world!"
{
"externalId": concat("some-prefix:", input.tag)
}

distinct_by

distinct_by(x, (a(, b)) => ...)

Returns a list or object where the elements are distinct by the returned value of the given lambda function. The lambda function either takes list values, or object (value, key) pairs.

Code example

[1, 2, 3, 4, 5].distinct_by(x => x % 2) -> [1, 2]

except

except(x, (v(, k)) => ...) or except(x, l)

Returns a list or object where keys or entries maching the predicate have been removed. If the second argument is a lambda, it will be given the entry and if it returns true, the entry is removed. If the second argument is a list, any entry also found in this list will be removed.

Code examples

{
"x-axis": 13.6,
"y-axis": 63.1,
"z-axis": 1.4,
"offset": 4.3,
"power": "on"
}.except(["offset", "power"])
->
{
"x-axis": 13.6,
"y-axis": 63.1,
"z-axis": 1.4
}
{
"a": 1,
"b": 2,
"c": 3,
"d": 4
}.except((v, k) => v > 2)
->
{
"a": 1,
"b": 2
}

filter

filter(x, it => ...)

Removes any item from the list x where the lambda function returns false or null.

Code examples

[1, 2, 3, 4].filter(item => item > 2) -> [3, 4]
input.data.map(row => {
"timestamp": to_unix_timestamp(row.StartTime, "%Y-%m-%dT%H:%M:%S"),
"value": try_float(row.Value, null),
"externalId": concat("prefix/", column.Name),
"type": "datapoint",
}).filter(dp => dp.value is "number")

flatmap

flatmap(x, it => ...)

Applies the lambda function to every item in the list x and flattens the result.

For example, if the lambda function returns a list, the result of the flatmap will just be a list instead of a list of lists.

Code examples

[[1, 2, 3], [2, 3, 4], [3, 4, 5]].flatmap(list => list.map(item => item + 1))
->
[2, 3, 4, 3, 4, 5, 4, 5, 6]
input.sensorData.flatmap(timeseries =>
timeseries.values.map(datapoint => {
"value": datapoint.value,
"timestamp": to_unix_timestamp(datapoint.datetime, "%Y-%m-%dT%H:%M:%S"),
"externalId": concat(timeseries.location, "/", timeseries.sensor),
"type": "datapoint"
})
)

float

float(x)

Converts x into a floating point number if possible. If the conversion fails, the whole mapping will fail.

Consider using try_float instead if you need error handling.

Code example

float("6.1") -> 6.1

floor

floor(x)

Returns x rounded down to the nearest integer.

Code example

floor(16.2) -> 16

format_timestamp

format_timestamp(x, f)

Converts the Unix timestamp x into a string representation based on the format f.

The format is given using the table found here.

Code examples

format_timestamp(1694159249120, "%Y-%m-%d %H:%M:%S") -> "2023-09-08 07:47:29"
format_timestamp(now(), "%d/%m - %Y") -> "08/09 - 2023"

if

if(x, y, (z))

Returns y if x evaluates to true, otherwise return z, or null if z is omitted.

Code examples

if(condition, "yes", "no")
if(true, "on", "off") -> "on"

int

int(x)

Converts x into an integer if possible. If the conversion fails, the whole mapping will fail.

Consider using try_int instead if you need error handling.

Code example

int("6") -> 6

join

join(a, b, ...)

Returns the union of the given objects or arrays. If a key is present in multiple objects, it is overwritten by the rightmost object. Arrays are simply merged.

Code examples

join({"key1": "value1"}, {"key2": "value2"})
->
{
"key1": "value1",
"key2": "value2"
}
join([1, 2, 3], [4, 5], [6, 7, 8])
->
[1, 2, 3, 4, 5, 6, 7, 8]

length

length(x)

Returns the length on the list, string or object x.

Code examples

length("Hello, world") -> 12
length([1, 2, 3]) -> 3
length(input.items)

log

log(x, y)

Returns the base y logarithm of x.

Code example

log(16, 2) -> 4.0

map

map(x, (it(, index)) => ...)

Applies the lambda function to every item in the list x. The lambda takes an optional second input which is the index of the item in the list.

If applied to an object, the first input is the value, and the second is the key. The result is the new value.

Code examples

[1, 2, 3, 4].map(number => number * 2) -> [2, 4, 6, 8]
input.data.map(item => {
"type": "datapoint",
"value": item.value,
"externalId": concat("prefix:", item.tag),
"timestamp": now()
})
["a", "b", "c"].map((item, index) => index)
->
[1, 2, 3]
{"a": 1, "b": 2, "c": 3}.map((value, key) => concat(value, key))
->
{"a": "1a", "b": "2b", "c": "3c"}

now

now()

Returns the current time as a millisecond Unix timestamp, that is, the number of milliseconds since midnight 1/1/1970 UTC.

Code example

{
"timestamp": now()
}

pairs

pairs(x)

Convert the object x into a list of key/value pairs.

Code examples

{
"a": 1,
"b": 2,
"c": 3
}.pairs()
->
[{
"key": "a",
"value": 1
}, {
"key": "b",
"value": 2
}, {
"key": "c",
"value": 3
}]
{
"x-axis": 12.4,
"y-axis": 17.3,
"z-axis": 2.1
}.pairs().map(kv => {
"timestamp": now(),
"value": kv.value,
"externalId": kv.key,
"type": "datapoint"
})

pow

pow(x, y)

Returns x to the power of y

Code example

pow(5, 3) -> 125.0

reduce

reduce(x, (acc, val) => ..., init)

Returns the value obtained by reducing the list x. The lambda function is called once for each element in the list val, and the returned value is passed as acc in the next iteration. The init will be given as the initial acc for the first call to the lambda function.

Code examples

[1, 2, 3, 4, 5].reduce((acc, val) => acc + val, 0) -> 15
[1, 2, 3, 4, 5].reduce((acc, val) => acc * val, 1) -> 120

replace

replace(a, b, c)

Replaces a string with another string

Code examples

"tomato".replace("tomato","potato") -> "potato"
replace("potato","o","a") -> "patata"

round

round(x)

Returns x rounded to the nearest integer.

Code example

round(16.2) -> 16

select

select(x, (v(, k)) => ...) or select(x, [1, 2, 3])

Returs a list or object where the lambda returns true. If the second argument is a list, the list values or object keys found in that list are used to select from the source.

Code examples

{
"x-axis": 13.6,
"y-axis": 63.1,
"z-axis": 1.4,
"offset": 4.3,
"power": "on"
}.select(["x-axis", "y-axis", "z-axis"])
->
{
"x-axis": 13.6,
"y-axis": 63.1,
"z-axis": 1.4
}
{
"a": 1,
"b": 2,
"c": 3
}.select((v, k) => v > 2)
->
{
"c": 3
}

slice

slice(x, start(, end))

Creates a sub-array from an array x from start to end. If end is not specified, go from startthe end of the array. Ifstartorend` are negative, count from the end of the array.

Code examples

[1, 2, 3, 4].slice(1, 3) -> [2, 3]
[1, 2, 3, 4].slice(0, -3) -> [1]

split

split(a, b)

Splits string a on any occurences of b. If b is an empty string, this will split on each character, including before the first and after the last.

Code examples

"hello world".split(" ") -> ["hello", "world"]
"hello".split("") -> ["", "h", "e", "l", "l", "o", ""]

string

string(x)

Converts x into a string.

nulls will be converted into empty strings.

Code example

string(true) -> "true"

substring

substring(x, start(, end))

Creates a substring of an input string x from start to end. If end is not specified, go from start to end of string. If start or end are negative, count from the end of the string.

Code examples

"hello world".substring(3, 8) -> "lo wo"
"hello world".substring(0, -3) -> "hello wo"

sum

sum(x)

Sums the numbers in the array x.

Code example

[1, 2, 3, 4].sum() -> 10

tail

tail(x(, n))

Takes the last element of the list x. If n is given, takes the last n elements, and returns a list if n > 1.

Code examples

[1, 2, 3, 4, 5].tail() -> 5
[1, 2, 3, 4, 5].tail(2) -> [4, 5]

to_object

to_object(x, val => ...(, val => ...))

Converts the array x into an object by producing the key and value from two lambdas.

The first lambda produces the key, and the second (optional) produces the value. If the second is left out, the input is used as a value directly.

Code examples

[1, 2, 3].to_object(v => string(v + 1)) -> { "2": 1, "3": 2, "4": 3 }
[1, 2, 3].to_object(v => string(v + 1), v => v - 1) -> { "2": 0, "3": 1, "4": 2 }
{"a": 1, "b": 2, "c": 3}.pairs().to_object(pair => pair.key, pair => pair.value) -> {"a": 1, "b": 2, "c": 3}

to_unix_timestamp

to_unix_timestamp(x, f)

Converts the string x into a millisecond Unix timestamp using the format string f.

The format is given using the table found here.

Code examples

to_unix_timestamp("2023-05-01 12:43:23", "%Y-%m-%d %H:%M:%S") -> 1682945003000
{
"timestamp": to_unix_timestamp(input.time, "%Y-%m-%d %H:%M:%S")
}

trim_whitespace

trim_whitespace(x)

Removes any whitespace from the start and end of x

Code example

"  hello   ".trim_whitespace() -> "hello"

try_bool

try_bool(a, b)

Try convert a to a boolean, if it fails, return b.

Code examples

try_bool("true", null) -> true
try_bool("foo", null) -> null

try_float

try_float(a, b)

Try convert a to a float, if it fails, return b.

Code examples

try_float("6.2", 1.2) -> 6.2
try_float("4,5", null) -> 4.5

try_int

try_int(a, b)

Try convert a to a int, if it fails, return b.

Code examples

try_int("6", 1) -> 6
try_int("4", null) -> 4

zip

zip(x, y, ..., (i1, i2, ...) => ...)

Takes a number of arrays, call the given lambda function on each entry, and return a single array from the result of each call. The returned array will be as long as the longest argument, null will be given for the shorter input arrays when they run out.

Code example

zip([1, 2, 3], ["a", "b", "c"], (a, b) => concat(a, b)) -> ["1a", "2b", "3c"]