How do you create an arbitray for a Map() object?

[dpnova]

I have code that uses .entries and none of the current map-ish arbs support that.

New user here so maybe I've missed something!

Thanks

[gruhn]

If your keys are strings, you can use fc.dictionary. For example

const arbitraryMap = fc.dictionary(fc.string(), fc.nat())
    .map(dict => new Map(Object.entries(dict)))

console.log( fc.sample(arbitraryMap, 5) )

Map(1) { 'CxbD!_' => 1135090401 },
Map(3) { 'q`' => 2113644272, ' x&~' => 27, '~}!t|z~y' => 25 },
Map(1) { '_#3' => 1738777444 },
Map(4) {
  '|call}&b #' => 9,
  '\\^!+L(' => 28,
  '' => 1752156948,
  'c' => 163999411
},
Map(7) {
  'I>U){' => 1984610647,
  'KEeeK' => 1524839195,
  'sAZ' => 937344058,
  '' => 529998270,
  'Gd2#<=ZHr}' => 1135358149,
  'a;kS4rzo' => 1594872950,
  ':(' => 641853712
}

[dpnova]

thanks @gruhn - I thought I was doing that, the type error for me seems to be on a nested field. In the screenshot you can see the ff function the line above the error where I have a function that takes a single instance of the nested type and the compiler is ok with that, it's just not ok when that appears as a value of a nested map.

[dpnova]

This counter example shows an object for items not a map. Arbitrary below - I tried forcing minKeys to stop it from using {} for items - but it still inserts an object, not a map.

[dpnova]

Oh I finally realised what your map was doing in your example!

Thanks! This was very hard to google for