Emit previous translation of an obsolete entry

Author: kisaragi-hiu

lib/pocompiler.js

@@ -70,9 +70,10 @@ function Compiler (table = {}, options = {}) {
  * in the form of {translator:'', reference: '', extracted: '', flag: '', previous:''}
  *
  * @param {Object} comments A comments object
+ * @param {boolean} [obsolete] This comments object is for an obsolete block
  * @return {String} A comment string for the PO file
  */
-Compiler.prototype._drawComments = function (comments) {
+Compiler.prototype._drawComments = function (comments, obsolete = false) {
   const lines = [];
   const types = [{
     key: 'translator',
@@ -88,7 +89,7 @@ Compiler.prototype._drawComments = function (comments) {
     prefix: '#, '
   }, {
     key: 'previous',
-    prefix: '#| '
+    prefix: obsolete ? '#~| ' : '#| '
   }];
 
   types.forEach(type => {
@@ -121,7 +122,7 @@ Compiler.prototype._drawBlock = function (block, override = {}, obsolete = false
   let comments = override.comments || block.comments;
 
   // add comments
-  if (comments && (comments = this._drawComments(comments))) {
+  if (comments && (comments = this._drawComments(comments, obsolete))) {
     response.push(comments);
   }