In Ruby, how to output json from hash and give it line breaks and tabs

Question

I\'m trying to format {\"key\" => \"value\"} to turn it into :

{
    \"key\" : \"value\"
}

for writing into a json file. ri

Answer 1

Yay for pretty things and yay for avoiding regexen!

Use the built-in JSON.pretty_generate method

require 'json'
puts JSON.pretty_generate hash, options

Yay!

Here's the options:

• indent: a string used to indent levels (default: ''),
• space: a string that is put after, a : or , delimiter (default: ''),
• space_before: a string that is put before a : pair delimiter (default: ''),
• object_nl: a string that is put at the end of a JSON object (default: ''),
• array_nl: a string that is put at the end of a JSON array (default: ''),
• allow_nan: true if NaN, Infinity, and -Infinity should be generated, otherwise an exception is thrown if these values are encountered. This options defaults to false.
• max_nesting: The maximum depth of nesting allowed in the data structures from which JSON is to be generated. Disable depth checking with :max_nesting => false, it defaults to 100.

Answer 2

As @naomik mentions, try using the builtin JSON.pretty_generate with a tab for the "indent" option, for example:

require 'json'
h = {:key => :value}
puts JSON.pretty_generate(h, :indent => "\t")
# {
#         "key": "value"
# }

The values for the "opts" argument to pretty_generate are documented at generate.

Answer 3

For both line breaks and tabs, try

require 'json'
hash = {foo: 'bar'}
JSON.pretty_generate(hash, {indent: "\t", object_nl: "\n"})

NB! If you use single quotes with newlines ("\n") or tabs ("\t") they will not be interpreted as newlines but as an ordinary string containing one backslash and a letter. This is a common mistake. :)