FMListToJSONArray ( key ; fmList )

Translate a FileMaker list into a proper JSON Array without recursion.

Average rating: 4.4 (5 votes) Log in to vote

Michael Twisdale - Show more from this author

Sample input:

FMListToJSONArray ( "car" ; "" )
FMListToJSONArray ( "" ; "" )
FMListToJSONArray ( "car" ; "¶Ford¶¶BMW¶" )

Sample output:

{"car":[""]}
[""]
{"car":["","Ford","","BMW",""]}

Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

/**
 * ====================================================================
 * FMListToJSONArray ( key ; fmList )
 *
 * PURPOSE:
 *                  Creates a JSON array in the form
 *                                    {
 *                                          "key": [
 *                                                            {"key0"    : "fmLlist_value1"},
 *                                                            {"key1"    : "fmLlist_value2"},
 *                                                            {"key2"    : "fmLlist_value3"},
 *                                                            {"keyN-1": "fmLlist_valueN"}
 *                                          ]
 *                                    }
 *
 *                  Given (1) a Filemaker List in the form
 * 
 *                                                                      
 *                                                     List ("value1"; 
 *                                                            "value2";
 *                                                            "value3";
 *                                                            "valueN")
 * 
 *                  and (2) a name for the Array. "key"
 *  
 *  
 *                  NOTE:
 *                            The JSONArray may be an anonymous, or unnamed, array, for example, ["fmLlist_value1", "fmLlist_value2", ….. "fmLlist_valueN"] .
 *  
 *                            Furthermore, the JSONArray may be Null for example, [""] .
 *  
 * 
 *  
 *  Example:
 *		    Filemaker list 
 *					List ( "Cat" ; "Bird" ; "IGuana" )
 *		    Array Nam3
 *					"Animal"
 * 
 *		    FMListToJSONArray  ( "Animal" ; List ( "Cat" ; "Bird" ; "IGuana" ) )  or FMListToJSONArray  ( "Animal" ; "Cat¶Bird¶Guana" ) )produces
 *					{"Animal":["Cat","Bird","IGuana"]}
 *
 *		    which is to say a JSON Arry in the form
 *
 *					["Animal[0]";"Cat";JSONString];
 *					["Animal[1]";"Bird";JSONString];
 *					["Animal[2]";"IGuana";JSONString]
 *
 *                  NOTE:
 *                            Each Filemaker ¶ indicates an array element before and an array element after.
 *
 *                            FMListToJSONArray  ( "Animal" ; "Cat¶Bird¶" ) )produces
 *					{"Animal":["Cat","Bird",""]}
 *
 *					or
 *
 *					["Animal[0]";"Cat";JSONString];
 *					["Animal[1]";"Bird";JSONString];
 *					["Animal[2]";"";JSONString]
 *
 *
 *
 * RETURNS:
 *                  (quoted string array) in the form: 
 *					{"key":["value1","value2","value3"]}, where any of the elements may be NULL ("").
 *                  
 * DEPENDENCIES: NONE
 *                  
 * NOTES:
 *                  Create a fast (non iterating) function to convert (in place) a FMList to proper JSONArray that can be used with Javascript
 *                  comments on seedcode blog post - "FileMaker 16 JSON Script Parameters" 
 * RELEASE:   Michael P, Twisdale — 5/28/2017     
 * ====================================================================
 * 
 */
Let ( [
	jtype = "JSONString" ;
	key = Quote ( key ) ; 

	vc1 = ValueCount ( fmList ) ; // ValueCount oof the List before processing
	fmList = "\"" & Substitute (   fmList ; ¶ ; "\"¶\"" ) & "\"";
	vc2 = ValueCount ( fmList ) ; // ValueCount oof the List after processing
	
	$$FMLJSA_key_Iter = "" ; // add FMLJSA as a name space for globals
	$$FMLJSA_key_Num = ValueCount ( fmList )-1 ;

	type = " & " & Quote ( "\";" ) & " & " & Quote ( jtype ) & " & " & Quote ( "]" ); // Quote and add separate quoted &
	
	let_list_Iterator =
		"Let ( [ $$FMLJSA_key_Iter = If ( IsEmpty ( $$FMLJSA_key_Iter ) ; $$FMLJSA_key_Num ; $$FMLJSA_key_Iter - 1 ) ] ;"   
	& Quote ( "[" )  & key & " & \"[\" & $$FMLJSA_key_Iter & \"]\"\";\\\"\" & " ;

	let_list_Iterator_End = If ( vc1>1  or vc2>1 ; " ) ;¶"  ; " )¶" ) ;

	jsonList = Evaluate ( 	

	If ( vc1>1  or vc2>1 ; 
		"List(¶"  ; "" ) &
		   let_list_Iterator & Substitute (  fmList ; ¶ ;  type &  " & " & Quote ( ";" ) & let_list_Iterator_End & let_list_Iterator )  & type & let_list_Iterator_End 
	& If ( vc1>1 or vc2>1 ; 
		")"  ; "" ) 
	) ;

	$$FMLJSA_key_Iter = ""		
	] ;

  Evaluate ( 	
	"JSONSetElement(" &  Quote ( "" ) & ";" & 
	jsonList & ")"
  )
)

For more see GitHub - twisdale/FMListToJSONArray: Translate a FileMaker list into a proper JSON Array .

Look at the Readme file.

Comments

		Lewis Lorenz, Lorenz Companies Jul 21, 2021
This is a great function. I ran into an issue where it does not produce valid JSON if a quotation mark (") is in a FM valuelist element. I tried using Quote on the valuelist and escaping the quote without success. Can you help with a solution? Thank you.

		Jason Lecureux Aug 27, 2024
Forgive my ignorance but what use cases does this cover as opposed to something simpler like: Let ( [ fmList = "[\"" & Substitute ( fmList; ¶ ; "\",\"" ) & "\"]" ;obj = JSONSetElement ( ""; "key"; fmList; "" ) ]; obj )

Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.

FMListToJSONArray ( key ; fmList )

Comments

Support this website.

Support this website.