You have the option to:
- identify groups of characters,
- determine the character and its frequency, and
- merge it into a single string.
In this code snippet:
function runLengthEncoding(string) {
return string
.match(/(.)\1*/g)
.map(s => s[0] + s.length)
.join('');
}
console.log(['a', 'aaa', 'aaabbc'].map(runLengthEncoding));
This version makes the process easier to understand by iterating through the given string, counting the characters encountered. When a different character is found, the previous character and its count are appended to the result string.
Additionally, the code now includes a verification step to prevent empty strings from being counted, adding the last character and its count to the final result.
function runLengthEncoding(string) {
var result = '',
i,
count = 0,
character = string[0];
for (i = 0; i < string.length; i++) {
if (character === string[i]) {
count++;
continue;
}
result += character + count;
character = string[i];
count = 1;
}
if (count) {
result += character + count;
}
return result;
}
console.log(['', 'a', 'aaa', 'aaabbc'].map(runLengthEncoding));