nested loops - must specify keys

example:

props => pug`
for row, y in props.grid
  for cell, x in row
    span(key=y*row.length + x)  #{cell}
`

workaround - use a flat array or insert a grouping element

props => pug`
for row, y in props.grid
  div(key=y)
    for cell, x in row
      span(key=x) #{cell}
`

[ezhlobo]

@ForbesLindesay @KittenHero so, my intention here is to let pug not care about keys at all. I don’t see any reason to validate the code before transpiling, because even React throws warnings instead of errors (like we do).

BTW, if we let people transpile the code without keys, they will still see the warnings from React in DEV mode.

If you strongly disagree, let me know.

[ezhlobo]

Done in v7.0.0

See how it works online

//CC @KittenHero