A lightweight, powerful, dependency-free and heavily over engineered TypeScript utility library providing utility types and functions to work with object paths in dot notation.
Dot notation is a popular and convenient way to access deeply nested properties in objects. With Dot Diver, you can safely work with object paths in TypeScript projects, ensuring complete type safety and avoiding runtime errors.
Example:
import { getByPath } from '@clickbar/dot-diver'
const object = {
a: 'Hello world',
}
const result = getByPath(object, 'a') // result is 'Hello world'- 🎯 Works with arrays, tuples, and objects
- 🛡️ Works with readonly properties
- ✅ Tests included
- 🌀 Works with cyclic dependencies in types
- 🚫 No dependencies
- 🪶 Tiny footprint
Install the package using your favorite package manager:
npm
npm install -D @clickbar/dot-diveryarn
yarn add -D @clickbar/dot-diverpnpm
pnpm install -D @clickbar/dot-diverimport { getByPath, setByPath } from '@clickbar/dot-diver'
// Define a sample object with nested properties
const object = {
a: 'hello',
b: {
c: 42,
d: {
e: 'world',
},
},
f: [{ g: 'array-item-1' }, { g: 'array-item-2' }],
}
// Example 1: Get a value by path
const value1 = getByPath(object, 'a') // Output: 'hello'
console.log(value1)
const value2 = getByPath(object, 'b.c') // Output: 42
console.log(value2)
const value3 = getByPath(object, 'b.d.e') // Output: 'world'
console.log(value3)
const value4 = getByPath(object, 'f.0') // Output: { g: 'array-item-1' }
console.log(value4)
const value5 = getByPath(object, 'f.1.g') // Output: 'array-item-2'
console.log(value5)
// Example 2: Set a value by path
setByPath(object, 'a', 'new hello')
console.log(object.a) // Output: 'new hello'
setByPath(object, 'b.c', 100)
console.log(object.b.c) // Output: 100
setByPath(object, 'b.d.e', 'new world')
console.log(object.b.d.e) // Output: 'new world'
setByPath(object, 'f.0', { g: 'new array-item-1' })
console.log(object.f[0]) // Output: { g: 'new array-item-1' }
setByPath(object, 'f.1.g', 'new array-item-2')
console.log(object.f[1].g) // Output: 'new array-item-2'Note
At the moment, we can not support object properties having a '.' in their name, since this would conflict with the dot notation traversal.
import type { Path, GetPathValue } from '@clickbar/dot-diver'
// Define a sample object type with nested properties
type MyObjectType = {
a: string
b: {
c: number
d: {
e: boolean
}
}
f: [{ g: string }, { g: string }]
}
// Example 1: Using the Path type
type MyObjectPaths = Path<MyObjectType>
// MyObjectPaths will be a union type representing all valid paths in dot notation:
// 'a' | 'b' | 'f' | 'b.c' | 'b.d' | 'b.d.e' | 'f.0' | 'f.1' | 'f.0.g' | 'f.1.g'
// Example 2: Using the GetPathValue type
type ValueAtPathA = GetPathValue<MyObjectType, 'a'> // Output: string
type ValueAtPathB_C = GetPathValue<MyObjectType, 'b.c'> // Output: number
type ValueAtPathB_D_E = GetPathValue<MyObjectType, 'b.d.e'> // Output: boolean
type ValueAtPathF_0 = GetPathValue<MyObjectType, 'f.0'> // Output: { g: string }
type ValueAtPathF_0_G = GetPathValue<MyObjectType, 'f.0.g'> // Output: stringimport type { Path, GetPathValue } from '@clickbar/dot-diver'
// Define an object type with nested properties and a cyclic dependency
type Node = {
id: number
label: string
parent: Node
children: Node[]
}
// Example 1: Using the Path type with the default depth limit
type NodePathsDepth2 = Path<Node> // Depth limit of 2
// NodePathsDepth2 will be a union type representing all valid paths in dot notation up to a depth of 2:
// 'id' | 'label' | 'parent' | 'children' | 'parent.id' | 'parent.label' | 'parent.parent' | 'parent.children' | `parent.parent.${any}` | `parent.children.${any}` | `children.${number}` | `children.${number}.${any}`
// Example 2: Using the Path type with a custom depth limit
type NodePathsDepth3 = Path<Node, never, { depth: 3; onlyWritable: false }> // Depth limit of 3
// With a depth limit of 3, NodePathsDepth3 will be a union type representing all valid paths in dot notation up to a depth of 3:
// 'id' | 'label' | 'parent' | 'children'
// | 'parent.id' | 'parent.label' | 'parent.parent' | 'parent.children' | `parent.parent.parent'
// | `parent.parent.parent' | 'parent.parent.children' | ... etc.The second parameter is an offset. You can provide a valid path to start the autocompletion from there.
This is used in getByPath and setByPath to provide autocompletion for the next levels, starting from the current path.
When using getByPath and setByPath, the Depth parameter is the lookahead depth and not the max depth.
The default depth is currently 3.
You can customize the set and get functions, by implementing your own variant and using the provided types.\
Here is an example where we customize the lookahead depth to 5:
import { getByPath, setByPath } from '@clickbar/dot-diver'
import type { Path, SearchableObject, GetPathValue, SetPathValue } from '@clickbar/dot-diver'
function getByPathDepth5<T extends SearchableObject, P extends Path<T, P, { depth: 5 }> & string>(
object: T,
path: P,
): GetPathValue<T, P> {
return getByPath(object, path) as GetPathValue<T, P>
}
function setByPathDepth5<
T extends SearchableObject,
P extends Path<T, P, { onlyWriteable: true; depth: 5 }> & string,
>(object: T, path: P, value: SetPathValue<T, P>): void {
setByPath(object, path, value as SetPathValue<T, P>)
}
export { getByPathDepth5 as getByPath, setByPathDepth5 as setByPath }The intersection between Path<T, P, { depth: 5 }> and string is necessary for TypeScript to successfully narrow down the type of P based on the user-provided path input.
Without the intersection, the path would just be of type Path<T, P, { depth: 5 }> and PathValueEntry would be a union of all possible return types.
By using the intersection, TypeScript is forced to apply the Path constraints and infer the type from the provided user input.
Paths get truncated, if they are unioned with a string. E.g. keyof T | string.
This should only happen in rare cases for objects looking like this:
type TestType = {
a: string
b: string
[key: string]: string
}If your object has nested properties, for example looking like this:
type TestType = {
a: string
b: {
c: string
}
[key: string]: string
}You will get autocompletion again, as soon as you typed the path to the nested object, e.g. b..
Your paths are not truncated. TypeScript will still validate them.
Some IDEs have problems with displaying children.${number} paths.
If you can, define the array as an tuple. This will include all paths in the autocompletion.
This happens if TypeScript reaches its maximum depth limit. This library should prevent this, but it can still happen if a object has a lot of cyclic dependencies.
For example:
type TestType = {
a: TestType
b: [TestType]
c: TestType[]
d: {
e: TestType
}
f: TestType
}You can try to decrease the lookahead depth of the autocompletion by reimplementing the getByPath and setByPath functions.
See this section.
If you would like to contribute to Dot Diver, feel free to fork the repository, make changes, and submit a pull request. We appreciate any help and feedback.
See CONTRIBUTING.md for more information.
Please see SECURITY for details.
Dot Diver is licensed under the MIT License.
🎉 Happy diving! 🌊