Extension::JsonForEachString Method

Syntax

Arguments

jsonCharacter

A JSON string.

expressionCharacter

An Xbasic expression used to format the value of fields in the JSON string.

fieldsCharacter

Default = "" (all fields). A comma delimited list of fields to process. If not specified, all fields are processed.

Returns

reformatted_jsonCharacter

Returns the processed JSON.

Description

For each string in json, evaluate the expression to 'replace' the string.

Discussion

The ForEachString() method can be used to process every string in a JSON object using an expression. The expression can be used to replace values in the JSON.

This method is similar to the Xbasic *for_each() function, except that it is designed to operate on property values in a JSON string.

For example:

dim json as c = <<%str%
{
    "name" : "name Smith " ,
    "alias" : [ "jj " , "name " ] ,
    "id"     : {
        "name" : "name_01 "
    }
}
%str%

Notice that the string 'name' appears in the above JSON as both a property name and also in a property value.

We want to change 'name' to 'John', without changing the names of any of the property values. Also, note that each property value has trailing spaces.

' change 'name' to 'John'

json = extension::json::ForEachString(json,"strtran(value,'name','John')")

'trim trailing spaces from each property value
json = extension::json::ForEachString(json,"trim(value)")

Result:

{
    "name" : "John Smith" ,
    "alias" : [ "jj" , "John" ] ,
    "id" : {
        "name" : "John_01"
    }
}

Notice that none of the property names were changed.

To restrict what properties are changed, a comma delimited list of field names can be passed in as the third argument to the ForEachString() method. For example, in the script below, only the 'name' fields are updated:

' only process fields called 'name':
? extension::JSON::ForEachString(json, "strtran(value,'name','John')","name")
= {
    "name" : "John Smith " ,
    "alias" : [ "jj " , "name " ] ,
    "id"     : {
        "name" : "John_01 "
    }
}