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Methods
fromBaseX(value, baseOrAlphabetopt, useCharacterMapopt, nullable, useChunksopt, nullable, valueIsNumberopt, nullable) → {String}
This function converts a based representation back to its original number or string value.
This is the mirror function to toBaseX() and expects a value encoded with that function. See that function
for implementation details, modes and restrictions.
The result of this function is always either a decimal number or a string, just as the input value. All numbers apart from decimal ones are returned as strings without prefix. So, decimal 5 will be the number 5, but the binary version will be the string "101".
You may define the base as an integer between 2 and 64 or as a custom alphabet in the same range. Integer based alphabets are generated using defined base alphabets, which are sliced if necessary. Custom alphabets are automatically sorted to match base64 are far as possible, pushing additional characters to the end, which are then sorted ascending by character value.
"{" and "}" are the only forbidden characters in a custom alphabet, since we need these to mark number values in
fromBaseX().
Numerical conversion keeps negative numbers negative and marks the result with a preceding "-".
Parameters:
| Name | Type | Attributes | Default | Description |
|---|---|---|---|---|
value |
Number | String | value to be decoded |
||
baseOrAlphabet |
Number | String | Array.<String> |
<optional> |
64 | either the numerical base to convert to (64, 36, ...) or the alphabet of characters to use in encoding; numerical bases must be between 2 and 64 (if the result is chunked, we need a base 3) |
useCharacterMap |
Boolean |
<optional> <nullable> |
true | set to true, to use a character map, based on btoa(), instead of numerical conversion |
useChunks |
Boolean |
<optional> <nullable> |
false | set to true, to add chunking to the numerical approach, converting the value in groups separated by a delimiter, which is the first letter of the base's alphabet |
valueIsNumber |
Boolean |
<optional> <nullable> |
false | if true, the given value is treated as a number for numerical conversion; this is necessary, since numbers such as binaries are defined as strings and are therefore not auto-detectable |
- Source:
- See:
Throws:
-
error if baseOrAlphabet is not usable
-
error character mapped decoding fails, due to missing token/unmatched alphabet
Returns:
- Type
- String
Example
fromBaseX('Zm9vYmFy')
=> 'foobar'
fromBaseX('16W33YPUS', 36)
=> 'äす'
fromBaseX('{-3C3}', 13)
=> -666
fromBaseX('q', 64, false, false, true)
=> 42
fromBaseX('U70R0DCN0F0DS04T0BQ040R0GCN0N0JSNA03TZ0J01S0K0N0KQOA0HRN0R0C', 36, true)
=> 'too-long-for-number-conversion'
fromBaseX('D3EF5D81F026D9DFDA970BBF17222402A47D5AD650CF6C2FE2102A494BCBDD0A2864C', 16, false, true)
=> 'too-long-for-number-conversion'