Take a nested Javascript object and flatten it, or unflatten an object with delimited keys
npm install @activeprospect/flat> [!NOTE]
> Originally forked to fix a bug where dot notation keys in a nested array were not unflattened,
> see https://github.com/activeprospect/flat/commit/27b5bfaaab986028dd9d8bb8027d5dce2e5a874b.
>
> Fork is maintained because LeadConduit is not set up to easily consume ES modules, and the
> upstream package only ships an ESM package. This lib contains equivalent code, but maintains
> a CommonJS file format for compatibility with all LeadConduit integrations and applications.
Take a nested Javascript object and flatten it, or unflatten an object with
delimited keys.
`` bash`
$ npm install flat
Flattens the object - it'll return an object one level deep, regardless of how
nested the original object was:
` javascript
const { 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 unflatten on an object:
` javascript
const { unflatten } = require('flat')
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 flatten will preserve arrays and their contents. This is disabled by default.
` javascript
const { 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:
` 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
const { 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 } }
// }
`
Transform each part of a flat key before and after flattening.
`javascript
const { flatten, unflatten } = require('flat')
flatten({
key1: {
keyA: 'valueI'
},
key2: {
keyB: 'valueII'
},
key3: { a: { b: { c: 2 } } }
}, {
transformKey: function(key){
return '__' + key + '__';
}
})
// {
// '__key1__.__keyA__': 'valueI',
// '__key2__.__keyB__': 'valueII',
// '__key3__.__a__.__b__.__c__': 2
// }
unflatten({
'__key1__.__keyA__': 'valueI',
'__key2__.__keyB__': 'valueII',
'__key3__.__a__.__b__.__c__': 2
}, {
transformKey: function(key){
return key.substring(2, key.length - 2)
}
})
// {
// key1: {
// keyA: 'valueI'
// },
// key2: {
// keyB: 'valueII'
// },
// key3: { a: { b: { c: 2 } } }
// }
`
flat is also available as a command line tool. You can run it with npx:
`sh`
npx flat foo.json
Or install the flat command globally:`
sh`
npm i -g flat && flat foo.json
Accepts a filename as an argument:
`sh`
flat foo.json
Also accepts JSON on stdin:
`sh``
cat foo.json | flat