Class NullDecoder

An alias for transform.

Takes a decoder of U and produces a decoder of the union of T | U.

Useful for composing decoders that can decode many types.

Example:

asString.or(asNumber) // produces a decoder for string | number
asString.or(asNumber).or(asBoolean)) // produces a decoder for string | number | boolean
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Similar to decode, but throws an error if decoding fails.

Makes it possible to apply some transformation on a decoded value.

const asInt = asNumber.transform(num => parseInt(num))
asInt.parse(117.565) // produces 117
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Applies an operation that can also fail to this decoder.

const asInt = asNumber.try(num => {
     if (Number.isInteger(number))  return success(num)
     else return failure("expected integer but got " + num)
})
asInt.parse(117.565) // throws error - $root: expected integer but got 117.565
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