Merge pull request #278 from redguardtoo/master

`js2-print-json-path' added

js2-mode.el

@@ -10878,6 +10878,67 @@ And, if CHECK-ACTIVATION-P is non-nil, use the value of TOKEN."
         (js2-check-activation-name s (or token js2-NAME)))
     name))
 
+;;; Use AST to extract semantic information
+
+(defun js2-get-element-index-from-array-node (elem array-node &optional hardcoded-array-index)
+  "Get index of ELEM from ARRAY-NODE or 0 and return it as string."
+  (let ((idx 0) elems (rlt hardcoded-array-index))
+    (setq elems (js2-array-node-elems array-node))
+    (if (and elem (not hardcoded-array-index))
+        (setq rlt (catch 'nth-elt
+                    (dolist (x elems)
+                      ;; We know the ELEM does belong to ARRAY-NODE,
+                      (if (eq elem x) (throw 'nth-elt idx))
+                      (setq idx (1+ idx)))
+                    0)))
+    (format "[%s]" rlt)))
+
+(defun js2-print-json-path (&optional hardcoded-array-index)
+  "Print the path to the JSON value under point, and save it in the kill ring.
+If HARDCODED-ARRAY-INDEX provided, array index in JSON path is replaced with it."
+  (interactive "P")
+  (let (previous-node current-node
+        key-name
+        rlt)
+
+    ;; The `js2-node-at-point' starts scanning from AST root node.
+    ;; So there is no way to optimize it.
+    (setq current-node (js2-node-at-point))
+
+    (while (not (js2-ast-root-p current-node))
+      (cond
+       ;; JSON property node
+       ((js2-object-prop-node-p current-node)
+        (setq key-name (js2-prop-node-name (js2-object-prop-node-left current-node)))
+        (if rlt (setq rlt (concat "." key-name rlt))
+          (setq rlt (concat "." key-name))))
+
+       ;; Array node
+       ((or (js2-array-node-p current-node))
+        (setq rlt (concat (js2-get-element-index-from-array-node previous-node
+                                                                 current-node
+                                                                 hardcoded-array-index)
+                          rlt)))
+
+       ;; Other nodes are ignored
+       (t))
+
+      ;; current node is archived
+      (setq previous-node current-node)
+      ;; Get parent node and continue the loop
+      (setq current-node (js2-node-parent current-node)))
+
+    (cond
+     (rlt
+      ;; Clean the final result
+      (setq rlt (replace-regexp-in-string "^\\." "" rlt))
+      (kill-new rlt)
+      (message "%s => kill-ring" rlt))
+     (t
+      (message "No JSON path found!")))
+
+    rlt))
+
 ;;; Indentation support (bouncing)
 
 ;; In recent-enough Emacs, we reuse the indentation code from

tests/json-path.el

@@ -0,0 +1,64 @@
+;;; tests/json-path.el --- Test of using js2-mode AST to print JSON path.
+
+;; Copyright (C) 2015  Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'js2-mode)
+
+(ert-deftest js2-json-path-with-actual-array-index ()
+  (with-temp-buffer
+    (insert "var a = { hello: [1, 2, [1,3,3,4, { world: { hell: { yes: [1,2, 'test'] } } }]] };")
+    (js2-mode)
+    (goto-char 0)
+    (search-forward "test")
+    (should (string= (js2-print-json-path) "hello[2][4].world.hell.yes[2]"))))
+
+(ert-deftest js2-json-path-pure-arrays ()
+  (with-temp-buffer
+    (insert "var a = [5, 1, 4, [ 4, [1, 2, [1, 3.9, 4, [1, 2, 'test',3]]]], 9, 9];")
+    (js2-mode)
+    (goto-char 0)
+    (search-forward "test")
+    (should (string= (js2-print-json-path) "[3][1][2][3][2]"))))
+
+(ert-deftest js2-json-path-key-is-numeric ()
+  (with-temp-buffer
+    (insert "var b = {hello: {3 : {world: {2: 'test'}}}};")
+    (js2-mode)
+    (goto-char 0)
+    (search-forward "test")
+    (should (string= (js2-print-json-path) "hello.3.world.2"))))
+
+(ert-deftest js2-json-path-not-found ()
+  (with-temp-buffer
+    (insert "console.log('test');")
+    (js2-mode)
+    (goto-char 0)
+    (search-forward "test")
+    (should (eq (js2-print-json-path) nil))))
+
+(ert-deftest js2-json-path-with-array-index-hardcoded ()
+  (with-temp-buffer
+    (insert "var a = { hello: [1, 2, [1,3,3,4, { world: { hell: { yes: [1,2, 'test'] } } }]] };")
+    (js2-mode)
+    (goto-char 0)
+    (search-forward "test")
+    (should (string= (js2-print-json-path 1) "hello[1][1].world.hell.yes[1]"))
+    (should (string= (js2-print-json-path 0) "hello[0][0].world.hell.yes[0]"))))