[Compressor] RLE Compressor implementation

Compression/RLE.js

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+/*
+ * RLE (Run Length Encoding) is a simple form of data compression.
+ * The basic idea is to represent repeated successive characters as a single count and character.
+ * For example, the string "AAAABBBCCDAA" would be encoded as "4A3B2C1D2A".
+ *
+ * @author - [ddaniel27](https://github.com/ddaniel27)
+ */
+
+function Compress(str) {
+ let compressed = ''
+ let count = 1
+
+ for (let i = 0; i < str.length; i++) {
+ if (str[i] !== str[i + 1]) {
+ compressed += count + str[i]
+ count = 1
+ continue
+ }
+
+ count++
+ }
+
+ return compressed
+}
+
+function Decompress(str) {
+ let decompressed = ''
+ let match = [...str.matchAll(/(\d+)(\D)/g)] // match all groups of digits followed by a non-digit character
+
+ match.forEach((item) => {
+ let [count, char] = [item[1], item[2]]
+ decompressed += char.repeat(count)
+ })
+
+ return decompressed
+}
+
+export { Compress, Decompress }

Compression/test/RLE.test.js

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+import { Compress, Decompress } from '../RLE'
+
+describe('Test RLE Compressor/Decompressor', () => {
+ it('Test - 1, Pass long repetitive strings', () => {
+ expect(Compress('AAAAAAAAAAAAAA')).toBe('14A')
+ expect(Compress('AAABBQQQQQFG')).toBe('3A2B5Q1F1G')
+ })
+
+ it('Test - 2, Pass compressed strings', () => {
+ expect(Decompress('14A')).toBe('AAAAAAAAAAAAAA')
+ expect(Decompress('3A2B5Q1F1G')).toBe('AAABBQQQQQFG')
+ })
+})