0304f0b · elk · git.iko.soy

4{-| Library for working with [JSON](https://en.wikipedia.org/wiki/JSON) values.

5

6# Json Values

7−@docs JsonValue

7+@docs Json

8

9# Strings

10@docs fromString, toString

25import JavaScript (JSObject, JSString)

26

27{-| This datatype can represent all valid values that can be held in a JSON

28−object. In Elm, a proper JSON object is represented as a (Dict String JsonValue)

28+object. In Elm, a proper JSON object is represented as a (Dict String Json)

29which is a mapping from strings to Json Values. -}

30−data JsonValue

30+data Json

31 = String String

32 | Number Float

33 | Boolean Bool

34 | Null

35− | Array [JsonValue]

35+ | Array [Json]

36− | Object (Dict.Dict String JsonValue)

36+ | Object (Dict.Dict String Json)

37

38

39-- String Converters

40

41−{-| Convert a `JsonValue` into a prettified string.

41+{-| Convert a `Json` into a prettified string.

42The first argument is a separator token (e.g. \" \", \"\\n\", etc.) that will

43be used for indentation in the prettified string version of the JSON. -}

44−toString : String -> JsonValue -> String

44+toString : String -> Json -> String

45toString sep v = JS.toString (Native.Json.toJSString sep v)

46

47{-| Convert a proper JSON object into a JavaScript string.

48Note that the type JSString seen here is not the same as the type constructor

49JsonString used elsewhere in this module. -}

50−toJSString : String -> JsonValue -> JSString

50+toJSString : String -> Json -> JSString

51toJSString = Native.Json.toJSString

52

53{-| Parse a string representation of a proper JSON object into

54its Elm representation. -}

55−fromString : String -> Maybe JsonValue

55+fromString : String -> Maybe Json

56fromString s = Native.Json.fromJSString (JS.fromString s)

57

58{-| Parse a JavaScript string representation of a proper JSON object into

59its Elm representation. -}

60−fromJSString : JSString -> Maybe JsonValue

60+fromJSString : JSString -> Maybe Json

61fromJSString = Native.Json.fromJSString

62

63−{-| Convert a JS object into a `JsonValue`. -}

63+{-| Convert a JS object into a `Json`. -}

64−fromJSObject : JSObject -> JsonValue

64+fromJSObject : JSObject -> Json

65fromJSObject = Native.Json.fromJSObject

66

67−{-| Convert a `JsonValue` into a `JSObject`. Paired with the

67+{-| Convert a `Json` into a `JSObject`. Paired with the

68[`JavaScript.Experimental` library](/docs/JavaScript/Experimental.elm),

69This lets you convert strings into Elm records:

70

72

73 stringToRecord str =

74 case fromString str of

75− Just jsonValue -> Just (JS.toRecord (toJSObject jsonValue))

75+ Just json -> Just (JS.toRecord (toJSObject json))

76 Nothing -> Nothing

77-}

78−toJSObject : JsonValue -> JSObject

78+toJSObject : Json -> JSObject

79toJSObject = Native.Json.toJSObject

80−

81− {-- Extract Elm values from Json values

82−

83− string : JsonValue -> String

84− string v = case v of { String s -> s ; _ -> "" }

85−

86− number : JsonValue -> Float

87− number v = case v of { Number n -> n ; _ -> 0 }

88−

89− boolean : JsonValue -> Bool

90− boolean v = case v of { Boolean b -> b ; _ -> False }

91−

92− array : JsonValue -> [JsonValue]

93− array v = case v of { Array a -> a ; _ -> [] }

94−

95− object : JsonValue -> Dict String JsonValue

96− object v = case v of { Object o -> o ; _ -> Dict.empty }

97−

98−

99− -- Extract Elm values from dictionaries of Json values

100−

101− {-| Find a value in a Json Object using the passed get function. If the key is

102− not found, this returns the given default/base value. -}

103− find get base =

104− let f key dict =

105− case Dict.lookup key dict of

106− Nothing -> base

107− Just v -> get v

108− in f

109−

110− {-| Find a string value in an Elm Json object. If the key is not found or the

111− value found is not a string, this returns the empty string. -}

112− findString : String -> Object -> String

113− findString = find string ""

114−

115− {-| Find a number value in an Elm Json object. If the key is not found or the

116− value found is not a number, this returns 0 -}

117− findNumber : String -> Object -> Float

118− findNumber = find number 0

119−

120− {-| Find a boolean value in an Elm Json object. If the key is not found or the

121− value found is not a boolean, this returns the False. -}

122− findBoolean : String -> Object -> Bool

123− findBoolean = find boolean False

124−

125− {-| Find an array value in an Elm Json object. If the key is not found or the

126− value found is not an array, this returns an empty list. -}

127− findArray : String -> Object -> [JsonValue]

128− findArray = find array []

129−

130− {-| Find an object value in an Elm Json object. If the key is not found or the

131− value found is not an object, this returns an empty object. -}

132− findObject : String -> Object -> Object

133− findObject = find object Dict.empty

134− --}