Style-HashSyntax.md

Pattern: Inconsistent hash syntax

Issue: -

Description

This rule checks hash literal syntax.

It can enforce either the use of the class hash rocket syntax or the use of the newer Ruby 1.9 syntax (when applicable).

A separate offense is registered for each problematic pair.

The supported styles are:

• ruby19 - forces use of the 1.9 syntax (e.g. {a: 1}) when hashes have all symbols for keys
• hash_rockets - forces use of hash rockets for all hashes
• no_mixed_keys - simply checks for hashes with mixed syntaxes
• ruby19_no_mixed_keys - forces use of ruby 1.9 syntax and forbids mixed syntax hashes

Examples

"EnforcedStyle => 'ruby19'"

# good
{a: 2, b: 1}
{:c => 2, 'd' => 2} # acceptable since 'd' isn't a symbol
{d: 1, 'e' => 2} # technically not forbidden

# bad
{:a => 2}
{b: 1, :c => 2}

"EnforcedStyle => 'hash_rockets'"

# good
{:a => 1, :b => 2}

# bad
{a: 1, b: 2}
{c: 1, 'd' => 5}

"EnforcedStyle => 'no_mixed_keys'"

# good
{:a => 1, :b => 2}
{c: 1, d: 2}

# bad
{:a => 1, b: 2}
{c: 1, 'd' => 2}

"EnforcedStyle => 'ruby19_no_mixed_keys'"

# good
{a: 1, b: 2}
{:c => 3, 'd' => 4}

# bad
{:a => 1, :b => 2}
{c: 2, 'd' => 3} # should just use hash rockets

Default configuration

Attribute	Value
EnforcedStyle	ruby19
SupportedStyles	ruby19, hash_rockets, no_mixed_keys, ruby19_no_mixed_keys
UseHashRocketsWithSymbolValues	false
PreferHashRocketsForNonAlnumEndingSymbols	false

Further Reading

• RuboCop - Style/HashSyntax
• https://github.com/bbatsov/ruby-style-guide#hash-literals