Take a nested Javascript object and flatten it, or unflatten an object with delimited keys.
$ npm install flatFlattens the object - it'll return an object one level deep, regardless of how nested the original object was:
var flatten = require('flat')
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:
var unflatten = require('flat').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 ..
Use a custom function to flatten the keyname. By default, the delimiter is inserted between prev and next
Here's an example that uses a colon (':') to prefix and delimit the keyname
var o = {
hello: {
world: {
again: 'good morning'
}}}
flatten(o, { keyname: function(prev, next) {
return prev
? prev + ':' + next
: ':' + next
}})
// {
// ':hello:world:again': 'good morning'
// }Use a custom function to unflatten the keyname. It returns an array of key names. This is the inverse of keyname. By default, the delimiter is used to split the name.
When enabled, both flat and unflatten will preserve arrays and their
contents. This is disabled by default.
var flatten = require('flat')
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:
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:
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.
var flatten = require('flat')
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 } }
// }