flat
    DefinitelyTyped icon, indicating that this package has TypeScript declarations provided by the separate @types/flat package

    5.0.2 • Public • Published

    flat Build Status

    Take a nested Javascript object and flatten it, or unflatten an object with delimited keys.

    Installation

    $ npm install flat

    Methods

    flatten(original, options)

    Flattens 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
    // }

    unflatten(original, options)

    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
    //         }
    //     }
    // }

    Options

    delimiter

    Use a custom delimiter for (un)flattening your objects, instead of ..

    safe

    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'
    //         }}
    //     ]
    // }

    object

    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' }
    // }

    overwrite

    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.

    maxDepth

    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 } }
    // }

    transformKey

    Transform each part of a flat key before and after flattening.

    var flatten = require('flat')
    var unflatten = require('flat').unflatten
     
    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 } } }
    // }

    Command Line Usage

    flat is also available as a command line tool. You can run it with npx:

    npx flat foo.json

    Or install the flat command globally:

    npm i -g flat && flat foo.json

    Accepts a filename as an argument:

    flat foo.json

    Also accepts JSON on stdin:

    cat foo.json | flat

    Install

    npm i flat

    DownloadsWeekly Downloads

    5,451,691

    Version

    5.0.2

    License

    BSD-3-Clause

    Unpacked Size

    26.6 kB

    Total Files

    7

    Last publish

    Collaborators

    • hughsk
    • timoxley