importcpp, importjs should allow accessing individual params in pattern

[timotheecour]

Example

this works:

func wrapToInt*(this: JsBigInt; bits: Natural): JsBigInt {.importjs:
  "(() => { const i = #, b = #; return BigInt.asIntN(b, i) })()".}

this doesn't work but should:
(EDIT)

func wrapToInt*(this: JsBigInt; bits: Natural): JsBigInt {.importjs: "BigInt.asIntN($3, $2)".}

(or at least something equivalently simple)
Note: $1 is for function name, so I'm starting at $2

Additional Information

devel 1.5.1 d2f4f25
related: timotheecour#488
related but different: #12150

[juancarlospaco]

You can not use $1 for arguments because thats the function name.

[timotheecour]

indeed; I updated the issue accordingly