Writing Better Code
This is our final pass at refactoring the code. Actually, there are two end results; the first using string methods reduces the original code by 43 lines to 18. The second, uses a regular expression to reduce the original code by 54 lines to just 7.
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How did all those line get removed? The original code and our first refactoring split out the sentences based on punctuation and then split the words delimited by spaces. But, there was no reason to process the words individually. And, then a trick with split eliminated a bunch more.
The changes to note are:
- Note the split method on line 6. When the separator, /([.|?|!])/ includes capturing parentheses, the separator—period, comma, or exclaimation in this case—is included in the returned array. Normally separators aren't included. This feature allows us to get rid of the array and loop (lines 11 - 16 in the original code and first refactoring) that kept track of the end-of-sentence punctuation. This also is the reason for adding the space on line 14.
- The search method is similar to indexOf but it uses regular expressions. The search expression finds the index of the first non-space character.
- Lines 12 and 13 separate the first letter and the remaining sentence discarding any leading spaces.
- Line 14 capitalizes the first letter, and converts the remaining letters to lower case in bulk. Whenever a builtin function can be used instead of script it is faster.
- Line 16 removes the first leading space added on line 14.
See the section on Regular Expressions to learn more about the RegExp objects used in split and search above and replace below. The code can be made smaller yet with regular expressions.
You may want to for reference
The replace method can take a regular expression for the string to replace and a function as the replacement. In this regular expression, the cnvrt function is passed a punctuation (except for the first sentence), space and character, since toUpperCase only affects a through z toUpperCase can be used on all three characters and have the desired results.
