Anonymous functions bind to references

[JanChec]

Code:

for i in [0..2]
  setTimeout (-> console.log(i)), i * 500
  i2 = JSON.parse(JSON.stringify(i))  # superdirty value copy
  setTimeout (-> console.log(i2)), i2 * 500 + 250

Output:

3
2
3
2
3
2

^ in 250ms intervals - good, also correct order.

Expected:

0
0
1
1
2
2

^ in 250ms intervals.

[JanChec]

This is by design, a common solution is binding values by wrapping in another function:

for i in [0..2]
  boundLog = (text) -> (-> console.log(text))
  setTimeout boundLog(i), i * 500
  (...)

Hm, maybe some syntactic sugar for this?

[vendethiel]

I think you want #2518.