ts-get

Alternative to lodash.get that makes it typed and cool as if optional chaining proposal is there.

Means you're not only safely navigate object, but you're also getting 100% autocomplete and type-safeness 🎉

Usage and examples

import get from 'ts-get'
 
 type SomeType = {
  optionalField?: string
  nested?: {
    dangerousAccess?: string
  }
 } | undefined | null
 
 const emptyObject: SomeType = {}
 const withOneOptionalField: SomeType = {
    optionalField: "value",
 }
 
 get(emptyObject, it => it.optionalField, "default") // -> "default"
 get(withOneOptionalField, it => it.optionalField, "default") // -> "value"
 get(withOneOptionalField, it => it.nested.dangerousAccess, "default") // -> "default"
 get(withOneOptionalField, it => it.unknownField, "default") // -> Type error, `unknownField` doesn't exist on type
 get(withOneOptionalField, it => it.optionalField, 5) // -> Type error, third argument is not assignable to type `string`

Difference with lodash.get behavior

• If your path gets null at the end, it will bail out to defaultValue or undefined. If you would like to get null returned anyway, just pass it as a defaultValue

Known issues/limitations:

• If your type field is of type null and only null or undefined your field will be of type {}[]. I have no idea how to fix it 🤷‍♂️ PR Welcome 😇🙏

type A = {
  field: null | undefined// -> {}[] inside of the callback and as return type too
}
 

• If you return not a primitive but an object, all its nested fields will be Required e.g. all undefined and null will be removed.

import get from 'ts-get'
type A = {
  field?: {
    optional?: string | null
  }
}
const input: A = {}
const res = get(input, it => it.field)
res // <== Will be inferred as { optional: string }, without null and ? (undefined) which is wrong, but seems to be impossible to infer.
 

You can solve this issue passing down generics implicitly

import get from 'ts-get'
type A = {
  field?: {
    optional?: string | null
  }
}
const input: A = {}
const res = get<A, A['field']>(input, it => it.field)
res // <== Will be inferred properly