varname- The name of the variable containing the JSON string to parse.
item- The name of the key whose value to return.
Multiple keys can be listed separated by a hierarchy delimeter, which will recursively index into a nested JSON string to retrieve a specific subkey's value.
separator- A single character that delimits a key hierarchy for nested indexing. Default is a period (.)
This value should not appear in the key or hierarchy of keys itself, except to delimit the hierarchy of keys.
c- For keys that reference a JSON array, return the number of items in the array.
This option has no effect on any other type of value.
This documentation was imported from Asterisk Version GIT-20-f8000daff570856e8