REGEX global 'i' not recognising the word 'He' with a capital letter and replacing it with 'She' but does recognise 'he'

Question

I would appreciate some guidance on where my error is.

At the moment, my code finds the word 'he' perfectly and replaces it with 'she'; however for some reason it ignores 'He' with a capital letter at the start of a sentence and replaces it with 'undefined'. I have included the global flag 'i' to ignore case sensitivity, but still, it does not work.

Here is my code:

var mapObj = {
      Childname : name,
      SchoolName : schoolName,
      he : 'she',
      his : 'her',
      him : 'her',
      himself : 'herself',
      she : 'he',
      her : 'his',
      herself : 'himself',
      boy : 'girl'
    };

Here is where the error likely is.

    for (var n = 0; n<data.length;n++) {
      let pattern = (gender === 'Male') ? new RegExp (/\b(Childname|SchoolName|she|her|herself|girl)\b/,'gi') : new RegExp(/\b(Childname|he|him|his|himself|boy)\b/,'gi')
      let changed = data[n][0].replace(pattern, function(matched){
        return mapObj[matched];
          });
          changedComments.push([changed])
          }
          destinationSheet.getRange(1,1,changedComments.length,changedComments[0].length).setValues(changedComments)

Any help here would be greatly appreciated.

Thank you!

Because in your map you don't have "He". You need to convert to lowercase — Mr. Hedgehog, Mar 14 '21 at 14:58

score 0 · Answer 1 · answered Mar 14 '21 at 14:54

The value of matched will be the substring that matches the pattern that you provide, so if your pattern is /he/gi, and the matched substring is He, then the returned substring match will still be He, which doesn't exist as a key in matchObj.

The simple way to fix this would be

let changed = data[n][0].replace(pattern, function(matched){
  return mapObj[matched.toLowerCase()];
});

score 0 · Accepted Answer · answered Mar 14 '21 at 14:54

It is beeing replaced with undefined because the match is He not he and you are returning return mapObj[matched]; - so return mapObj['He']; - which is undefined.

return mapObj[matched.toLowerCase()]; would work, but then your replaced text would start with a lowercase she. So you should also add a check if the first letter is uppeercase like here for example and then uppercase the first letter of your replacement like here if its required.

REGEX global 'i' not recognising the word 'He' with a capital letter and replacing it with 'She' but does recognise 'he'

2 Answers2