Js object copy, deep copy and shallow copy

1) One line deep copy object/array with reduce

const deepCopyArr = arr => arr.reduce((acc, cur) => (
  cur instanceof Array ? [...acc, deepCopyArr(cur)] : [...acc, cur]
), [])
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2) One line implements deep copy objects

const deepCopyObj = obj => Object.entries(obj).reduce((acc, [key, value]) => ( typeof value === 'object' ? {... acc, [key]: deepCopyFun(value) } : { ... acc, [key]: value } ), {})Copy the code