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idle_zealot • last Tuesday at 9:43 PM • 2 replies • view on HN

Huh. I always thought that JS objects supported string and number keys separately, like lua. Nope!

  [Documents]$ cat test.js
  let testArray = [];
  testArray[0] = "foo";
  testArray["0"] = "bar";
  console.log(testArray[0]);
  console.log(testArray["0"]);
  [Documents]$ jsc test.js
  bar bar
  [Documents]$

Replies

nvlled • yesterday at 3:20 AM

Lua supports even functions and objects as keys:

  function f1() end
  function f2() end
  local m1 = {}
  local m2 = {}
  local obj = {
      [f1] = 1,
      [f2] = 2,
      [m1] = 3,
      [m2] = 4,
  }
  print(obj[f1], obj[f2], obj[m1], obj[m2], obj[{}])
Functions as keys is handy when implementing a quick pub/sub.
aidenn0 • last Tuesday at 10:25 PM

They do, but strings that are numbers will be reinterpreted as numbers.

[edit]

  let testArray = [];
  testArray[0] = "foo";
  testArray["0"] = "bar";
  testArray["00"] = "baz";
  console.log(testArray[0]);
  console.log(testArray["0"]);
  console.log(testArray["00"]);
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