(arr)

array literals and array patterns (destructuring)

(arr elems?)

Where:

1. elems: element constraints to apply within the array (use (el ...) to target position and/or value) *

Matching:

1. array literals, e.g. [a, b]
2. array patterns, e.g. [a, b] = coords

Behavior

• Does not match Array constructor calls like new Array(1, 2) or Array.from(...).
• Use (el) to constrain elements; (arr (el)) only matches non-empty arrays.

Examples

Review arrays of allowed HTTP methods that include DELETE.

(arr (el _ (str "DELETE")))

Selects in lines { 1, 3 } but not in { 2 }:

const methods1 = ["GET", "DELETE"]
const methods2 = ["GET", "POST"]
const methods3 = ["DELETE", "POST"]

---

Find locale arrays that default to English so the default can be changed.

(arr (el 1 (str "en")))

Selects in lines { 1, 3 } but not in { 2 }:

const locales1 = ["en", "fr"]
const locales2 = ["fr", "en"]
const locales3 = ["en", "es", "de"]

---

Identify tuple route declarations [method, path, handler] for migration.

(arr (:and (el 1 (str /GET|POST|DELETE/)) (el 3 (fun))))

Selects in lines { 2, 3 } but not in { 4, 5 }:

const routes = [
  ["GET", "/health", () => {}],
  ["POST", "/users", createUser],
  ["OPTIONS", "/users", options],
  ["GET", "/admin", admin, { auth: true }]
]

---

Arguments

elems

• (el)
• (:into) • (:and) • (:or) • (:not) • (:text) • (:kind) • (:replace) • (:capture)