Objects

values and lookup are typed against the object's declared fields — lookup infers the union of field types.

keysObjects

keys(value: object): string[]

Property names (merged across elements for an array of objects).

valuesObjects

values(value: object): unknown[]

Property values, typed as the union of the object's field types.

lookupObjects

lookup(value: object, key: string): unknown

Value of the given key (mapped over an array of objects).

mergeObjects

merge(objects: object[]): object

Merges an array of objects left to right.

spreadObjects

spread(value: object): object[]

Splits an object into an array of single-property objects.

typeObjects

type(value: unknown): string

`"string" | "number" | "boolean" | "null" | "array" | "object" | "undefined"`.

keys

keys(value: object): string[]

Property names (merged across elements for an array of objects).

headerNames: keys(req.headers)

values

values(value: object): unknown[]

Property values, typed as the union of the object's field types.

headerValues: values(req.headers)

lookup

lookup(value: object, key: string): unknown

Value of the given key (mapped over an array of objects).

host: lookup(req.headers, "host")

merge

merge(objects: object[]): object

Merges an array of objects left to right.

settings: merge([defaults, user.overrides])

spread

spread(value: object): object[]

Splits an object into an array of single-property objects.

entries: spread(req.headers)

type

type(value: unknown): string

"string" | "number" | "boolean" | "null" | "array" | "object" | "undefined".

kind: type(req.headers)

Playground

Mapping✔Playground ↗

input req: { headers: { host: string, accept: string } }

map {
  headerNames: keys(req.headers),
  host: lookup(req.headers, "host"),
  merged: merge([{ a: 1 }, { b: 2 }]),
  kind: type(req.headers),
}

input req: { headers: { host: string, accept: string } } map { headerNames: keys(req.headers), host: lookup(req.headers, "host"), merged: merge([{ a: 1 }, { b: 2 }]), kind: type(req.headers), }

Input JSON

{ "headers": { "host": "example.dev", "accept": "application/json" } }

{ "headers": { "host": "example.dev", "accept": "application/json" } }

Output

{
  "headerNames": [
    "host",
    "accept"
  ],
  "host": "example.dev",
  "merged": {
    "a": 1,
    "b": 2
  },
  "kind": "object"
}

inferred type{ headerNames: string[]; host?: string; merged: any; kind: string; }