dot-prop

> Get, set, or delete a property from a nested object using a dot path

Install

``sh
npm install dot-prop
`

Usage

`js
import {getProperty, setProperty, hasProperty, deleteProperty} from 'dot-prop';

// Getter
getProperty({foo: {bar: 'unicorn'}}, 'foo.bar');
//=> 'unicorn'

getProperty({foo: {bar: 'a'}}, 'foo.notDefined.deep');
//=> undefined

getProperty({foo: {bar: 'a'}}, 'foo.notDefined.deep', 'default value');
//=> 'default value'

getProperty({foo: {'dot.dot': 'unicorn'}}, 'foo.dot\\.dot');
//=> 'unicorn'

getProperty({foo: [{bar: 'unicorn'}]}, 'foo[0].bar');
//=> 'unicorn'

getProperty({foo: [{bar: 'unicorn'}]}, 'foo.0.bar');
//=> 'unicorn'

// Setter
const object = {foo: {bar: 'a'}};
setProperty(object, 'foo.bar', 'b');
console.log(object);
//=> {foo: {bar: 'b'}}

const foo = setProperty({}, 'foo.bar', 'c');
console.log(foo);
//=> {foo: {bar: 'c'}}

setProperty(object, 'foo.baz', 'x');
console.log(object);
//=> {foo: {bar: 'b', baz: 'x'}}

setProperty(object, 'foo.biz[0]', 'a');
console.log(object);
//=> {foo: {bar: 'b', baz: 'x', biz: ['a']}}

setProperty(object, 'foo.items.0', 'first');
console.log(object);
//=> {foo: {bar: 'b', baz: 'x', biz: ['a'], items: ['first']}}

// Has
hasProperty({foo: {bar: 'unicorn'}}, 'foo.bar');
//=> true

// Deleter
const object = {foo: {bar: 'a'}};
deleteProperty(object, 'foo.bar');
console.log(object);
//=> {foo: {}}

object.foo.bar = {x: 'y', y: 'x'};
deleteProperty(object, 'foo.bar.x');
console.log(object);
//=> {foo: {bar: {y: 'x'}}}
`

$3

For improved performance and interoperability with other libraries, you can also pass paths as arrays instead of strings. This avoids the overhead of parsing string paths.

`js
import {getProperty, setProperty} from 'dot-prop';

const object = {
users: [
{name: 'Alice', role: 'admin'},
{name: 'Bob', role: 'user'}
]
};

// Using array paths - no parsing overhead
getProperty(object, ['users', 0, 'name']);
//=> 'Alice'

setProperty(object, ['users', 1, 'role'], 'moderator');
console.log(object.users[1].role);
//=> 'moderator'

// Useful for interoperability with libraries that return paths as arrays
const pathFromOtherLib = ['users', 0, 'profile', 'settings'];
setProperty(object, pathFromOtherLib, {theme: 'dark'});
`

Array paths:
- Avoid the parse/stringify cycle when you already have path segments
- Work with all functions: getProperty, setProperty, hasProperty, deleteProperty
- Numeric strings are automatically normalized to numbers for simplicity

API

$3

Get the value of the property at the given path.

Returns the value if any.

$3

Set the property at the given path to the given value.

Returns the object.

$3

Check whether the property at the given path exists.

Returns a boolean.

$3

Delete the property at the given path.

Returns a boolean of whether the property existed before being deleted.

$3

Escape special characters in a path. Useful for sanitizing user input.

`js
import {getProperty, escapePath} from 'dot-prop';

const object = {
foo: {
bar: '👸🏻 You found me Mario!',
},
'foo.bar' : '🍄 The princess is in another castle!',
};
const escapedPath = escapePath('foo.bar');

console.log(getProperty(object, escapedPath));
//=> '🍄 The princess is in another castle!'
`

$3

Parse a dot path into an array of path segments.

Returns an array of path segments where numbers represent array indices and strings represent object keys.

`js
import {parsePath} from 'dot-prop';

parsePath('foo.bar');
//=> ['foo', 'bar']

parsePath('foo[0].bar');
//=> ['foo', 0, 'bar']

parsePath('foo.0.bar');
//=> ['foo', 0, 'bar']

parsePath('foo\\.bar');
//=> ['foo.bar']

// Use case: Iterate over path segments to build up a nested object
const path = 'users[0].profile.settings.theme';
const segments = parsePath(path);
//=> ['users', 0, 'profile', 'settings', 'theme']
`

$3

Convert an array of path segments back into a path string.

Returns a string path that can be used with other dot-prop functions.

`js
import {stringifyPath} from 'dot-prop';

stringifyPath(['foo', 'bar']);
//=> 'foo.bar'

stringifyPath(['foo', 0, 'bar']);
//=> 'foo[0].bar'

stringifyPath(['foo', '0', 'bar']);
//=> 'foo[0].bar'

// With preferDotForIndices option
stringifyPath(['foo', 0, 'bar'], {preferDotForIndices: true});
//=> 'foo.0.bar'
`

#### pathSegments

Type: Array

Array of path segments where numbers represent array indices and strings represent object keys.

#### options

Type: object

##### preferDotForIndices

Type: boolean\
Default: false

When true, numeric indices will use dot notation instead of bracket notation when not the first segment.

$3

Returns an array of every path. Non-empty plain objects and arrays are deeply recursed and are not themselves included.

This can be useful to help flatten an object for an API that only accepts key-value pairs or for a tagged template literal.

`js
import {getProperty, deepKeys} from 'dot-prop';

const user = {
name: {
first: 'Richie',
last: 'Bendall',
},
activeTasks: [],
currentProject: null
};

for (const property of deepKeys(user)) {
console.log(${property}: ${getProperty(user, property)});
//=> name.first: Richie
//=> name.last: Bendall
//=> activeTasks: []
//=> currentProject: null
}
`

Sparse arrays are supported. In general, avoid using sparse arrays.

#### object

Type: object | array

Object or array to get, set, or delete the path value.

You are allowed to pass in undefined as the object to the get and has functions.

#### path

Type: string | Array

Path of the property in the object.

String paths: Use . to separate each nested key. Use \\. if you have a . in the key. Array indices can be accessed using bracket notation (like 'users[0].name') or dot notation (like 'users.0.name'). Both syntaxes are equivalent and will create arrays when setting values. Numeric strings in dot notation (like 'users.0.name') are automatically coerced to numbers.

Array paths: Pass an array of path segments for better performance and interoperability. Numbers create arrays (like ['users', 0, 'name']). Numeric strings are normalized to numbers for simplicity. No parsing overhead.

The following path components are invalid and results in undefined being returned: __proto__, prototype, constructor.

#### value

Type: unknown

Value to set at path.

#### defaultValue

Type: unknown

Default value.

$3

Convert an object with dot paths into a nested object.

Uses the same path rules and escaping as the rest of the API.

`js
import {unflatten} from 'dot-prop';

const flat = {
'unicorn.name': 'Rainbow Dash',
'unicorn.color': '🦄',
'unicorn.treasures[0]': 'sparkles',
'unicorn.treasures[1]': 'glitter',
};

unflatten(flat);
/*
{
unicorn: {
name: 'Rainbow Dash',
color: '🦄',
treasures: ['sparkles', 'glitter']
}
}
*/
``