StrawHat v0.6.0 StrawHat.Response View Source
Utilities for working with "result tuples".
{:ok, value}
{:error, reason}
Link to this section Summary
Functions
Calls the next function only if it receives an ok tuple. Otherwise it skips the call and returns the error tuple.
Calls the first function if it receives an error tuple, and the second one if it receives an ok tuple.
Creates a new error result tuple.
Checks if a result_tuple
is an error.
Promotes any value to a result tuple.
Converts an Ok
value to an Error
value if the predicate
is not valid.
Calls the next function only if it receives an ok tuple. The function unwraps the value from the tuple, calls the next function and wraps it back into an ok tuple.
Calls the next function only if it receives an error tuple. The function unwraps the value from the tuple, calls the next function and wraps it back into an error tuple.
Creates a new ok result tuple.
Checks if a result_tuple
is ok.
Calls the next function only if it receives an error tuple. Otherwise it skips the call and returns the ok tuple. It expects the function to return a new result tuple.
Converts an Ok
value to an Error
value if the predicate
is valid.
Transforms a list of result tuple to a result tuple containing either the first error tuple or an ok tuple containing the list of values.
Calls the next function only if it receives an ok tuple but discards the result. It always returns the original tuple.
Calls the next function only if it receives an error tuple but discards the result. It always returns the original tuple.
Returns the content of an ok tuple if the value is correct. Otherwise it returns the default value.
Link to this section Types
Link to this section Functions
and_then(error, function)
View Sourceand_then(result_tuple(), (any() -> result_tuple())) :: result_tuple()
Calls the next function only if it receives an ok tuple. Otherwise it skips the call and returns the error tuple.
Examples
iex> business_logic = fn x -> StrawHat.Response.ok(x * 2) end
...> 21 |> StrawHat.Response.ok() |> StrawHat.Response.and_then(business_logic)
{:ok, 42}
iex> business_logic = fn x -> StrawHat.Response.ok(x * 2) end
...> "oops" |> StrawHat.Response.error() |> StrawHat.Response.and_then(business_logic)
{:error, "oops"}
Calls the first function if it receives an error tuple, and the second one if it receives an ok tuple.
Examples
iex> on_ok = fn x -> "X is #{x}" end
...> on_error = fn e -> "Error: #{e}" end
...> 42 |> StrawHat.Response.ok() |> StrawHat.Response.either(on_error, on_ok)
"X is 42"
iex> on_ok = fn x -> "X is #{x}" end
...> on_error = fn e -> "Error: #{e}" end
...> "oops" |> StrawHat.Response.error() |> StrawHat.Response.either(on_error, on_ok)
"Error: oops"
Creates a new error result tuple.
Examples
iex> StrawHat.Response.error("oops")
{:error, "oops"}
Checks if a result_tuple
is an error.
Examples
iex> 1 |> StrawHat.Response.ok() |> StrawHat.Response.error?()
false
iex> 2 |>StrawHat.Response.error() |> StrawHat.Response.error?()
true
Promotes any value to a result tuple.
It excludes nil
for the ok tuples.
Examples
iex> StrawHat.Response.from_value(nil)
{:error, :no_value}
iex> StrawHat.Response.from_value(nil, "Missing")
{:error, "Missing"}
iex> StrawHat.Response.from_value(42)
{:ok, 42}
iex> StrawHat.Response.from_value({:ok, 123})
{:ok, 123}
iex> StrawHat.Response.from_value({:error, "my error"})
{:error, "my error"}
keep_if(result, predicate, error_message \\ :invalid)
View Sourcekeep_if(result_tuple(), (any() -> boolean()), any()) :: result_tuple()
Converts an Ok
value to an Error
value if the predicate
is not valid.
Examples
iex> res = StrawHat.Response.ok(10)
...> StrawHat.Response.keep_if(res, &(&1 > 5))
{:ok, 10}
iex> res = StrawHat.Response.ok(10)
...> StrawHat.Response.keep_if(res, &(&1 > 10), "must be > of 10")
{:error, "must be > of 10"}
iex> res = StrawHat.Response.error(:no_value)
...> StrawHat.Response.keep_if(res, &(&1 > 10), "must be > of 10")
{:error, :no_value}
map(error, function)
View Sourcemap(result_tuple(), (any() -> any())) :: result_tuple()
Calls the next function only if it receives an ok tuple. The function unwraps the value from the tuple, calls the next function and wraps it back into an ok tuple.
Examples
iex> business_logic = fn x -> x * 2 end
...> 21 |> StrawHat.Response.ok() |> StrawHat.Response.map(business_logic)
{:ok, 42}
iex> business_logic = fn x -> x * 2 end
...> "oops" |> StrawHat.Response.error() |> StrawHat.Response.map(business_logic)
{:error, "oops"}
map_error(data, function)
View Sourcemap_error(result_tuple(), (any() -> any())) :: result_tuple()
Calls the next function only if it receives an error tuple. The function unwraps the value from the tuple, calls the next function and wraps it back into an error tuple.
Examples
iex> better_error = fn _ -> "A better error message" end
...> 42 |> StrawHat.Response.ok() |> StrawHat.Response.map_error(better_error)
{:ok, 42}
iex> better_error = fn _ -> "A better error message" end
...> "oops" |> StrawHat.Response.error() |> StrawHat.Response.map_error(better_error)
{:error, "A better error message"}
Creates a new ok result tuple.
Examples
iex> StrawHat.Response.ok(42)
{:ok, 42}
Checks if a result_tuple
is ok.
Examples
iex> 1 |> StrawHat.Response.ok() |> StrawHat.Response.ok?()
true
iex> 2 |> StrawHat.Response.error() |>StrawHat.Response.ok?()
false
or_else(data, function)
View Sourceor_else(result_tuple(), (any() -> result_tuple())) :: result_tuple()
Calls the next function only if it receives an error tuple. Otherwise it skips the call and returns the ok tuple. It expects the function to return a new result tuple.
Examples
iex> business_logic = fn _ -> {:error, "a better error message"} end
...> {:ok, 42} |> StrawHat.Response.or_else(business_logic)
{:ok, 42}
iex> business_logic = fn _ -> {:error, "a better error message"} end
...> {:error, "oops"} |> StrawHat.Response.or_else(business_logic)
{:error, "a better error message"}
iex> default_value = fn _ -> {:ok, []} end
...> {:error, "oops"} |> StrawHat.Response.or_else(default_value)
{:ok, []}
reject_if(result, predicate, error_message \\ :invalid)
View Sourcereject_if(result_tuple(), (any() -> boolean()), any()) :: result_tuple()
Converts an Ok
value to an Error
value if the predicate
is valid.
Examples
iex> res = StrawHat.Response.ok([])
...> StrawHat.Response.reject_if(res, &Enum.empty?/1)
{:error, :invalid}
iex> res = StrawHat.Response.ok([1])
...> StrawHat.Response.reject_if(res, &Enum.empty?/1)
{:ok, [1]}
iex> res = StrawHat.Response.ok([])
...> StrawHat.Response.reject_if(res, &Enum.empty?/1, "list cannot be empty")
{:error, "list cannot be empty"}
sequence(list)
View Sourcesequence([result_tuple()]) :: {:ok, [any()]} | {:error, any()}
Transforms a list of result tuple to a result tuple containing either the first error tuple or an ok tuple containing the list of values.
Examples
iex> StrawHat.Response.sequence([StrawHat.Response.ok(42), StrawHat.Response.ok(1337)])
{:ok, [42, 1337]}
iex> StrawHat.Response.sequence([StrawHat.Response.ok(42), StrawHat.Response.error("oops"), StrawHat.Response.ok(1337)])
{:error, "oops"}
tap(data, function)
View Sourcetap(result_tuple(), (any() -> any())) :: result_tuple()
Calls the next function only if it receives an ok tuple but discards the result. It always returns the original tuple.
Examples
iex> some_logging = fn x -> "Success #{x}" end
...> {:ok, 42} |> StrawHat.Response.tap(some_logging)
{:ok, 42}
iex> some_logging = fn _ -> "Not called logging" end
...> {:error, "oops"} |> StrawHat.Response.tap(some_logging)
{:error, "oops"}
tap_error(data, function)
View Sourcetap_error(result_tuple(), (any() -> any())) :: result_tuple()
Calls the next function only if it receives an error tuple but discards the result. It always returns the original tuple.
Examples
iex> some_logging = fn x -> "Failed #{x}" end ...> {:error, "oops"} |> StrawHat.Response.tap_error(some_logging)
iex> somelogging = fn -> "Not called logging" end ...> {:ok, 42} |> StrawHat.Response.tap_error(some_logging)
with_default(arg, default_data)
View Sourcewith_default(result_tuple(), any()) :: any()
Returns the content of an ok tuple if the value is correct. Otherwise it returns the default value.
Examples
iex> 42 |> StrawHat.Response.ok |> StrawHat.Response.with_default(1337)
42
iex> "oops" |> StrawHat.Response.error |> StrawHat.Response.with_default(1337)
1337