class JSON::Builder

• JSON::Builder
• Reference
• Object

Overview

A JSON builder generates valid JSON.

A JSON::Error is raised if attempting to generate an invalid JSON (for example, if invoking #end_array without a matching #start_array, or trying to use a non-string value as an object's field name).

Defined in:

Constructors

• .new(io : IO)

  Creates a JSON::Builder that will write to the given IO.

Instance Method Summary

• #array(&)

  Writes the start of an array, invokes the block, and the writes the end of it.

• #bool(value : Bool) : Nil

  Writes a boolean value.

• #document(&)
• #end_array : Nil

  Writes the end of an array.

• #end_document : Nil

  Signals the end of a JSON document.

• #end_object : Nil

  Writes the end of an object.

• #field(name, value)

  Writes an object's field and value.

• #field(name, &)

  Writes an object's field and then invokes the block.

• #flush

  Flushes the underlying IO.

• #indent=(string : String)

  Sets the indent string.

• #indent=(level : Int)

  Sets the indent level (number of spaces).

• #max_nesting : Int32

  By default the maximum nesting of arrays/objects is 99.

• #max_nesting=(max_nesting : Int32)

  By default the maximum nesting of arrays/objects is 99.

• #next_is_object_key? : Bool

  Returns true if the next thing that must pushed into this builder is an object key (so a string) or the end of an object.

• #null : Nil

  Writes a #null value.

• #number(number : Int) : Nil

  Writes an integer.

• #number(number : Float) : Nil

  Writes a float.

• #object(&)

  Writes the start of an object, invokes the block, and the writes the end of it.

• #raw(string : String) : Nil

  Writes a raw value, considered a scalar, directly into the IO without processing.

• #scalar(value : Nil)

  Writes a scalar value.

• #scalar(value : Bool)

  Writes a scalar value.

• #scalar(value : Int | Float) : Nil

  Writes a scalar value.

• #scalar(value : String) : Nil

  Writes a scalar value.

• #start_array : Nil

  Writes the start of an array.

• #start_document : Nil

  Starts a document.

• #start_object : Nil

  Writes the start of an object.

• #string(value) : Nil

  Writes a string with the content of value.

• #string(& : IO -> ) : Nil

  Writes a string with the contents written to the yielded IO.

Constructor Detail

Instance Method Detail

JSON.build do |builder|
  builder.string("foo")
end # => %("foo")
JSON.build do |builder|
  builder.string([1, 2])
end # => %("[1, 2]")

JSON.build do |builder|
  builder.string do |io|
    io << "foo"
    io << [1, 2]
  end # => %("foo[1, 2]")
end