I have the following typescript in my test script:

const tmdBytes = Bytes.hex_encode("ipfs://xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")
const tmdMap : Array<[ string, Bytes ]> = [" ", tmdBytes]

The second line is giving me the errors:

Type 'string' is not assignable to type '[string, Bytes]'.
Type 'Bytes' is not assignable to type '[string, Bytes]'. 

I have tried to copy the example in the docs which is:

const ledger : Array<[ Address, Int ]> = []

The errors of course go away if I remove the values from the array, copying the docs exactly, but then I don't know how to add the values to the Map/Array.

My goal is to pass this array as a parameter in a test script, eg:

    await fa2_contract.mint(

Any help appreciated, thanks.

2 Answers 2


I think you should try with this:

const tmdMap : Array<[ string, Bytes ]> = [[" ", tmdBytes]]

In typescript, tuple and array have the same literal []. And here, it is a tuple into an array.


The expected type reads "an array of pairs of string and bytes", and [" ", tmdBytes] is just a pair, hence I guess the following value should make ti:

const tmdMap : Array<[ string, Bytes ]> = [ [" ", tmdBytes] ]

As a side note, maps/assets are transpiled to arrays of pairs (asset) key and (asset) value, and the TS syntax for both arrays and tuples is [ ]. The reason for not transpiling to TS map objects is because the types of keys in TS maps does not deal easily with complex/composed keys.

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