Class: StringCompressor

Constructor

          
            1new StringCompressor(dictionary = {}, flag = '$')
          
        

Parameters:

• dictionary – Optional initial dictionary mapping original strings to compressed keys. Defaults to {}.
• flag – Prefix for compressed keys. Defaults to $.

Example:

          
            1const compressor = new StringCompressor({}, '#');
          
        

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setDictionary(dictionary)

Sets a new dictionary and automatically generates a reverse dictionary for decompression.

Parameters:

• dictionary – Object mapping original strings to short keys.

Example:

          
            1compressor.setDictionary({ hello: '$a', world: '$b' });
          
        

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compress(str, dictionary = null)

Compresses a string using the current dictionary. Optionally, a new dictionary can be passed.

Parameters:

• str – The string to compress.
• dictionary – Optional dictionary to override current one.

Example:

          
            1const compressed = compressor.compress("hello world hello");2// "$a $b $a"
          
        

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decompress(str, dictionary = null)

Decompresses a string using the current reverse dictionary. Optionally, a new dictionary can be passed.

Parameters:

• str – The string to decompress.
• dictionary – Optional dictionary to override current one.

Example:

          
            1const decompressed = compressor.decompress("$a $b $a");2// "hello world hello"
          
        

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generateMap(str, minLength = 4, minFreq = 2, flag)

Generates a compression dictionary automatically based on word frequency in the input string.

Parameters:

• str – Input string.
• minLength – Minimum length of words to consider. Defaults to 4.
• minFreq – Minimum frequency of words to include. Defaults to 2.
• flag – Optional flag prefix for keys. Defaults to the instance flag.

Returns: Dictionary object mapping words to short keys.

Example:

          
            1const map = compressor.generateMap("hello world hello world", 3, 2);2// { hello: '$a', world: '$b' }
          
        

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generateAndSetDictionary(str, minLength = 4, minFreq = 2, flag)

Generates a frequency-based dictionary and sets it as the current dictionary.

Returns: Dictionary object.

Example:

          
            1compressor.generateAndSetDictionary("hello world hello world");2// Dictionary now set: { hello: '$a', world: '$b' }
          
        

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stats(originalStr, compressedStr)

Provides statistics on compression efficiency.

Parameters:

• originalStr – Original string.
• compressedStr – Compressed string.

Returns: Object with:

• originalLength – Length of original string.
• compressedLength – Length of compressed string.
• saved – Number of characters saved.
• percentSaved – Percentage reduction as string.

Example:

          
            1const stats = compressor.stats("hello world hello", "$a $b $a");2console.log(stats);3// { originalLength: 17, compressedLength: 9, saved: 8, percentSaved: '47.06%' }
          
        

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replace(str, map)

Replaces occurrences of keys in a string based on a mapping object.

Example:

          
            1compressor.replace("hello world", { hello: '$a', world: '$b' });2// "$a $b"
          
        

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Edge Cases & Notes:

• Supports Unicode words via \p{L} regex.
• Generates short keys using patterns like a, b, ..., z, aa, ab.
• Words shorter than minLength or below frequency threshold are ignored.
• Safe to use on strings without dictionary; returns original string unchanged if mapping is empty.

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