Take a nested Javascript object and flatten it, or unflatten an object with delimited keys
npm install flatleyTake a nested Javascript object and flatten it, or unflatten an object with
delimited keys.
Based on 'flat' by Hugh Kennedy (http://hughskennedy.com)
`` bash`
$ npm install flatley
Flattens the object - it'll return an object one level deep, regardless of how
nested the original object was:
` javascript
var flatten = require('flatley')
flatten({
key1: {
keyA: 'valueI'
},
key2: {
keyB: 'valueII'
},
key3: { a: { b: { c: 2 } } }
})
// {
// 'key1.keyA': 'valueI',
// 'key2.keyB': 'valueII',
// 'key3.a.b.c': 2
// }
`
Flattening is reversible too, you can call flatten.unflatten() on an object:
` javascript
var unflatten = require('flatley').unflatten
unflatten({
'three.levels.deep': 42,
'three.levels': {
nested: true
}
})
// {
// three: {
// levels: {
// deep: 42,
// nested: true
// }
// }
// }
`
Use a custom delimiter for (un)flattening your objects, instead of ..
When enabled, both flat and unflatten will preserve arrays and their
contents. This is disabled by default.
` javascript
var flatten = require('flatley')
flatten({
this: [
{ contains: 'arrays' },
{ preserving: {
them: 'for you'
}}
]
}, {
safe: true
})
// {
// 'this': [
// { contains: 'arrays' },
// { preserving: {
// them: 'for you'
// }}
// ]
// }
`
When enabled, arrays will not be created automatically when calling unflatten, like so:
` javascript
unflatten({
'hello.you.0': 'ipsum',
'hello.you.1': 'lorem',
'hello.other.world': 'foo'
}, { object: true })
// hello: {
// you: {
// 0: 'ipsum',
// 1: 'lorem',
// },
// other: { world: 'foo' }
// }
`
When enabled, existing keys in the unflattened object may be overwritten if they cannot hold a newly encountered nested value:
`javascript
unflatten({
'TRAVIS': 'true',
'TRAVIS_DIR': '/home/travis/build/kvz/environmental'
}, { overwrite: true })
// TRAVIS: {
// DIR: '/home/travis/build/kvz/environmental'
// }
`
Without overwrite set to true, the TRAVIS key would already have been set to a string, thus could not accept the nested DIR element.
This only makes sense on ordered arrays, and since we're overwriting data, should be used with care.
Maximum number of nested objects to flatten.
` javascript
var flatten = require('flatley')
flatten({
key1: {
keyA: 'valueI'
},
key2: {
keyB: 'valueII'
},
key3: { a: { b: { c: 2 } } }
}, { maxDepth: 2 })
// {
// 'key1.keyA': 'valueI',
// 'key2.keyB': 'valueII',
// 'key3.a': { b: { c: 2 } }
// }
`
Optionally run a test/set of tests on your incoming key/value(s) and transform the resulting value if it matches.
This is particularly useful in the case of transforming https://www.npmjs.com/package/mongoose ObjectIds
`javascript
var ObjectId = mongoose.Types.ObjectId
var coercion = [{
test: function (key, value) { return key === '_id' && ObjectId.isValid(value) }
transform: function (value) { return value.valueOf() }
}]
var options = { coercion: coercion }
flatten({
group1: {
prop1: ObjectId('aaabbbcccdddeee')
}
}, options)
// {
// 'group1.prop1': 'aaabbbcccdddeee'
// }
`
Optionally run a test/set of tests on your incoming key/value(s) and don't transform this key's children if it matches.
`javascript
const someObject = {
prop1: 'abc',
prop2: 'def'
}
var filters = [{
test: function (key, value) { return value.prop1 === 'abc' }
}]
var options = { filters: filters }
flatten({
group1: {
someObject: someObject
}
}, options)
// {
// 'group1.someObject': {
// 'prop1': 'abc',
// 'prop2': 'def'
// }
// }
``