Module | DeepMerge |
In: |
lib/deep_merge/deep_merge_hash.rb
lib/deep_merge/rails_compat.rb lib/deep_merge/core.rb |
DEFAULT_FIELD_KNOCKOUT_PREFIX | = | '--' |
Deep Merge core documentation. deep_merge! method permits merging of arbitrary child elements. The two top level elements must be hashes. These hashes can contain unlimited (to stack limit) levels of child elements. These child elements to not have to be of the same types. Where child elements are of the same type, deep_merge will attempt to merge them together. Where child elements are not of the same type, deep_merge will skip or optionally overwrite the destination element with the contents of the source element at that level. So if you have two hashes like this:
source = {:x => [1,2,3], :y => 2} dest = {:x => [4,5,'6'], :y => [7,8,9]} dest.deep_merge!(source) Results: {:x => [1,2,3,4,5,'6'], :y => 2}
By default, "deep_merge!" will overwrite any unmergeables and merge everything else. To avoid this, use "deep_merge" (no bang/exclamation mark)
Options:
Options are specified in the last parameter passed, which should be in hash format: hash.deep_merge!({:x => [1,2]}, {:knockout_prefix => '--'}) :preserve_unmergeables DEFAULT: false Set to true to skip any unmergeable elements from source :knockout_prefix DEFAULT: nil Set to string value to signify prefix which deletes elements from existing element :sort_merged_arrays DEFAULT: false Set to true to sort all arrays that are merged together :unpack_arrays DEFAULT: nil Set to string value to run "Array::join" then "String::split" against all arrays :merge_hash_arrays DEFAULT: false Set to true to merge hashes within arrays :merge_debug DEFAULT: false Set to true to get console output of merge process for debugging
Selected Options Details: :knockout_prefix => The purpose of this is to provide a way to remove elements
from existing Hash by specifying them in a special way in incoming hash source = {:x => ['--1', '2']} dest = {:x => ['1', '3']} dest.ko_deep_merge!(source) Results: {:x => ['2','3']} Additionally, if the knockout_prefix is passed alone as a string, it will cause the entire element to be removed: source = {:x => '--'} dest = {:x => [1,2,3]} dest.ko_deep_merge!(source) Results: {:x => ""}
:unpack_arrays => The purpose of this is to permit compound elements to be passed
in as strings and to be converted into discrete array elements irsource = {:x => ['1,2,3', '4']} dest = {:x => ['5','6','7,8']} dest.deep_merge!(source, {:unpack_arrays => ','}) Results: {:x => ['1','2','3','4','5','6','7','8'} Why: If receiving data from an HTML form, this makes it easy for a checkbox to pass multiple values from within a single HTML element
:merge_hash_arrays => merge hashes within arrays
source = {:x => [{:y => 1}]} dest = {:x => [{:z => 2}]} dest.deep_merge!(source, {:merge_hash_arrays => true}) Results: {:x => [{:y => 1, :z => 2}]}
There are many tests for this library - and you can learn more about the features and usages of deep_merge! by just browsing the test examples
allows deep_merge! to uniformly handle overwriting of unmergeable entities