object-rewrite
Rewrite an Object by defining exactly what gets filtered, injected and retained.
Install
npm i --save object-rewrite
Getting Started
Modifies the data object in place. If you need to create a copy consider using _.deepClone().
const objectRewrite = require('object-rewrite');
const data = [{
guid: 'aad8b948-a3de-4bff-a50f-3d59e9510aa9',
count: 3,
active: 'yes',
tags: [{ id: 1 }, { id: 2 }, { id: 3 }]
}, {
guid: '4409fb72-36e3-4385-b3da-b4944d028dcb',
count: 4,
active: 'yes',
tags: [{ id: 2 }, { id: 3 }, { id: 4 }]
}, {
guid: '96067a3c-caa2-4018-bcec-6969a874dad9',
count: 5,
active: 'no',
tags: [{ id: 3 }, { id: 4 }, { id: 5 }]
}];
const rewriter = objectRewrite({
filter: {
'': (key, value, parents) => value.active === 'yes',
tags: (key, value, parents) => value.id === 4
},
inject: {
'': (key, value, parents) => ({ countNext: value.count + 1 })
},
overwrite: {
active: (key, value) => value === 'yes'
},
retain: ['count', 'countNext', 'active', 'tags.id']
});
rewriter(data);
The empty needle ""
matches top level object(s).
Modifiers
Needles are specified according to object-scan.
Internally the option useArraySelector
is set to false.
Functions have signature Fn(key, value, parents)
as specified by object-scan. Keys are split (joined
is false),
Filter
Takes object where keys are needles and values are functions. The matches for a needle are removed from the object iff the corresponding function execution returns false.
Inject
Takes object where keys are needles and values are functions. For every match the corresponding function is executed and the result merged into the match. The match and the function response are expected to be objects.
Overwrite
Takes object where keys are needles and values are functions. For every match the corresponding function is executed and the result is assigned to the key.
Retain
Array of needles. Matches are kept if not filtered previously. All entries not matched are removed. Defaults to ["**"]
which matches all entries.
Options
retainEmptyParents
Type: boolean
Default: true
When false
, empty "parents" are only retained when exactly matched by retain
array entry. When true
, empty parents are also retained if a retain
array entry targets a "child".
Deficiencies
Problems when different matchers are used between filter, inject, overwrite, retain that target the same elements.
E.g. using **
for retain, but *.field
for inject.