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lwhorton/why-clojure#3.clj

Created March 18, 2018 02:08
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why-clojure#3.clj
Raw
why-clojure#3.clj
(let [old {:a 1 :b 2}
new-o (assoc old :c 3)]
(prn old) ;; {:a 1 :b 2}
)
(let [arr [1 2 3]
new-a (conj arr 4)]
(prn arr) ;; [1 2 3]
)
(let [obj-arr [{:a 1} {:b 2} {:c 3}]
new-o-a (assoc obj-arr 1 {:b -2})]
(prn obj-arr) ;; {:a 1} {:b 2} {:c 3}]
(prn new-o-a) ;; {:a 1} {:b -2} {:c 3}]
)
Raw
why-clojure#3.js
var old = {a: 1, b: 2}
var newO = Object.assign({}, {...old, c: 3})
console.log(old) // { a: 1, b: 2 }
var arr = [1, 2, 3]
var newA = [...arr, 4]
console.log(arr) // [1, 2, 3]
// what about updates/insertions? careful not to miss any ellipses or slices or off-by-ones
var objArr = [{a: 1}, {b: 2}, {c: 3}]
var newOA = [...objArr.slice(0, idx), {...objArr[idx], b: -2}, ...objArr.slice(idx+1)]
console.log(objArr) // [{a: 1}, {b: 2}, {c: 3}]
console.log(newOA) // [{a: 1}, {b: -2}, {c: 3}]
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