Dot notation with space padded key

Setup

Selector: $. a 

{" a": 1, "a": 2, " a ": 3, "": 4}

Results

Other responses

Bash (JSONPath.sh) 

[
  3
]

C (json-glib) 

[
  3
]

Clojure (json-path) ¹ 

2

Cpp (jsoncons) 

[
  2
]

Dart (json_path)

Not supported

Instance of 'ParserException': end of input expected (at 1:2)

Elixir (ExJsonPath) 

[
  2
]

Elixir (jaxon) 

[
  3
]

Elixir (warpath) ¹ 

2

Erlang (ejsonpath) 

[
  2
]

Golang (github.com-PaesslerAG-jsonpath) ¹ 

2

Golang (github.com-bhmj-jsonslice) ¹ ³ 

2

Golang (github.com-ohler55-ojg)

Not supported

Golang (github.com-oliveagle-jsonpath) ¹ 

3

Golang (github.com-spyzhov-ajson) 

[
  3
]

Golang (github.com-theory-jsonpath)

Not supported

jsonpath: unexpected blank space at position 3

Golang (github.com-vmware-labs-yaml-jsonpath)

Not supported

child name missing at position 2, following "$."

Haskell (jsonpath)

Not supported

Invalid JSONPath: $. a 
 Error: 1:3:
  |
1 | $. a 
  |   ^
unexpected space
expecting '.' or white space

JavaScript (Goessner) ² 

[
  3
]

JavaScript (brunerd)

Not supported

JavaScript (jsonpath)

Not supported

Lexical error on line 1. Unrecognized text.
$. a 
--^

JavaScript (jsonpath-plus) 

[
  3
]

JavaScript (jsonpathly) 

[
  2
]

Java (com.github.jsurfer) 

[
  2
]

Java (com.github.xmljacquard.ajp)

Not supported

Error at char 18 in expression in xsl:sequence/@select on line 20 column 67 of ajp-runner.xslt:
   <failed xmlns:ixml="http://invisiblexml.org/NS"
  ixml:state="failed"><line>1</line><column>3</column><pos>3</pos><unexpected>
  </unexpected><permitted>'*', '_', [#80-'퟿[xd7ff]'], ['A'-'Z'; 'a'-'z'], ['𐀀[x10000]'-'􏿯[x10ffef]'],
  ['[xe000]'-'￯[xffef]']</permitted><could-be-next><in rule="ALPHA"><tokens>['A'-'Z';
  'a'-'z']</tokens></in><in rule="wildcard-selector"><tokens>'*'</tokens></in><in
  rule="name-first"><tokens>'_', [#80-'퟿[xd7ff]'], ['𐀀[x10000]'-'􏿯[x10ffef]'],
  ['[xe000]'-'￯[xffef]']</tokens></in></could-be-next><unfinished><open rule="child-segment" start="2"
  end="2"><input>.</input></open><open rule="jsonpath-query" start="1"
  end="1"><input>$</input></open></unfinished></failed>
During lazy evaluation of tailCallLoop(ajp:getProcessor(...)) on line 20 of jar:file:./implementations/Java_com.github.xmljacquard.ajp/build/deps/org/xmljacquard/ajp/0.0.7/ajp-0.0.7.jar!/xslt/ajp-runner.xslt
In function ajpr:getProcessor on line 17 column 106 of ajp-runner.xslt:
net.sf.saxon.s9api.SaxonApiException: <failed xmlns:ixml="http://invisiblexml.org/NS" ixml:state="failed"><line>1</line><column>3</column><pos>3</pos><unexpected> </unexpected><permitted>'*', '_', [#80-'퟿'], ['A'-'Z'; 'a'-'z'], ['𐀀'-'􏿯'], [''-'￯']</permitted><could-be-next><in rule="ALPHA"><tokens>['A'-'Z'; 'a'-'z']</tokens></in><in rule="wildcard-selector"><tokens>'*'</tokens></in><in rule="name-first"><tokens>'_', [#80-'퟿'], ['𐀀'-'􏿯'], [''-'￯']</tokens></in></could-be-next><unfinished><open rule="child-segment" start="2" end="2"><input>.</input></open><open rule="jsonpath-query" start="1" end="1"><input>$</input></open></unfinished></failed>

Java (com.jayway.jsonpath) ¹ ³

Not supported

SLF4J(W): No SLF4J providers were found.
SLF4J(W): Defaulting to no-operation (NOP) logger implementation
SLF4J(W): See https://www.slf4j.org/codes.html#noProviders for further details.
com.jayway.jsonpath.InvalidPathException: Could not parse token starting at position 2

Kotlin (com.nfeld.jsonpathkt) ¹ 

1

Objective-C (SMJJSONPath) ¹ ³

Not supported

Could not parse token starting at position 2

PHP (Goessner) ² 

[
  3
]

PHP (galbar-jsonpath)

Not supported

Invalid JSONPath error: 'Error in JSONPath near '. a ''

PHP (remorhaz-jsonpath)

Not supported

Error: 'Failed to build AST from JSONPath query: $. a '

PHP (softcreatr-jsonpath)

Not supported

Error: 'Unable to parse token  a in expression: . a'

Perl (JSON-Path) 

[
  3
]

Python (jsonpath) ² 

[
  3
]

Python (jsonpath-ng) 

[
  2
]

Python (jsonpath-rw) 

[
  2
]

Python (jsonpath2) 

[
  2
]

Python (python-jsonpath)

Not supported

JSONPathSyntaxError('expected a shorthand selector')

Raku (JSON-Path)

Not supported

JSON path parse error at position 1

Ruby (jsonpath) 

[
  1
]

Rust (jsonpath)

Not supported

parsing error

Rust (jsonpath_lib)

Not supported

path error: 
$. a 
^^

Rust (serde_json_path)

Not supported

at position 2, in dot member name, must start with lowercase alpha or '_'

Scala (jsonpath) 

[
  2
]

Swift (Sextant)

Not supported

NOT_SUPPORTED

dotNET (Json.NET)

Not supported

Unexpected character while parsing path:

dotNET (JsonCons.JsonPath) 

[
  2
]

dotNET (JsonPath.Net) 

[
  1
]

dotNET (JsonPathLib) 

[
  3
]

dotNET (Manatee.Json)

Not supported

Unrecognized JSON Path element. Path up to error: '$'

Errors

JavaScript (json-p3) 

unexpected whitespace after dot ('$. a ':3)

Rust (jsonpath_plus) 

Error Parsing JSON Path:
$. a 
panic occurred

Footnotes